diff --git a/docs/quickstart.rst b/docs/quickstart.rst
index efd6d348630..560048d6999 100644
--- a/docs/quickstart.rst
+++ b/docs/quickstart.rst
@@ -11,7 +11,7 @@ Install a package from `PyPI`_:
     [...]
     Successfully installed SomePackage
 
-Install a package already downloaded from `PyPI`_ or got elsewhere.
+Install a package already downloaded from `PyPI`_ or obtained via other means.
 This is useful if the target machine does not have a network connection:
 
 ::
@@ -39,11 +39,11 @@ List what packages are outdated:
   $ pip list --outdated
     SomePackage (Current: 1.0 Latest: 2.0)
 
-Upgrade a package:
+To upgrade an existing package, simply run the install command again:
 
 ::
 
-  $ pip install --upgrade SomePackage
+  $ pip install SomePackage
     [...]
     Found existing installation: SomePackage 1.0
     Uninstalling SomePackage:
diff --git a/docs/reference/pip_install.rst b/docs/reference/pip_install.rst
index 6dac31e8c02..e5de9a53979 100644
--- a/docs/reference/pip_install.rst
+++ b/docs/reference/pip_install.rst
@@ -758,13 +758,6 @@ Examples
       $ pip install -r requirements.txt
 
 
-#. Upgrade an already installed `SomePackage` to the latest from PyPI.
-
-    ::
-
-      $ pip install --upgrade SomePackage
-
-
 #. Install a local project in "editable" mode. See the section on :ref:`Editable Installs <editable-installs>`.
 
     ::
diff --git a/docs/user_guide.rst b/docs/user_guide.rst
index 6bffdc22a4b..22363b68734 100644
--- a/docs/user_guide.rst
+++ b/docs/user_guide.rst
@@ -472,32 +472,29 @@ $ pip install --no-index --find-links=DIR -r requirements.txt
 "Only if needed" Recursive Upgrade
 **********************************
 
-``pip install --upgrade`` is currently written to perform an eager recursive
-upgrade, i.e. it upgrades all dependencies regardless of whether they still
-satisfy the new parent requirements.
+``pip install``, now, defaults to performs a "only if needed" recursive
+upgrade, i.e. it upgrades dependencies only when they no longer satisfy the
+new parent requirements. This was not always the case.
 
-E.g. supposing:
+Before pip 9.0, the upgrade behaviour defaulted to a different "eager"
+upgrade, i.e. it used to upgrade all dependencies regardless of whether they
+already satisfied the new parent requirements. This behaviour was seen as
+problematic and was replaced with the current behaviour in pip 9.0. This
+section contained instructions on how to work around the problematic
+behaviour. The recommended fix for that behaviour, now, is to upgrade to
+pip 9.0 or greater.
 
-* `SomePackage-1.0` requires `AnotherPackage>=1.0`
-* `SomePackage-2.0` requires `AnotherPackage>=1.0` and `OneMorePackage==1.0`
-* `SomePackage-1.0` and `AnotherPackage-1.0` are currently installed
-* `SomePackage-2.0` and `AnotherPackage-2.0` are the latest versions available on PyPI.
+See :issue:`59` and :issue:`3786` for the discussion on this change in
+behaviour.
 
-Running ``pip install --upgrade SomePackage`` would upgrade `SomePackage` *and*
-`AnotherPackage` despite `AnotherPackage` already being satisfied.
 
-pip doesn't currently have an option to do an "only if needed" recursive
-upgrade, but you can achieve it using these 2 steps::
+As an historic note, the fix for the behaviour was::
 
-  pip install --upgrade --no-deps SomePackage
-  pip install SomePackage
+    pip install --upgrade --no-deps SomePackage
+    pip install SomePackage
 
-The first line will upgrade `SomePackage`, but not dependencies like
-`AnotherPackage`.  The 2nd line will fill in new dependencies like
-`OneMorePackage`.
-
-See :issue:`59` for a plan of making "only if needed" recursive the default
-behavior for a new ``pip upgrade`` command.
+A proposal for an ``upgrade-all`` command is being considered as a safer
+alternative to the earlier behaviour of eager upgrading.
 
 
 User Installs
@@ -565,10 +562,6 @@ From within a real python, where ``SomePackage`` *is* installed globally, but is
 
   $ pip install --user SomePackage
   [...]
-  Requirement already satisfied (use --upgrade to upgrade)
-
-  $ pip install --user --upgrade SomePackage
-  [...]
   Successfully installed SomePackage
 
 
@@ -576,10 +569,6 @@ From within a real python, where ``SomePackage`` *is* installed globally, and is
 
   $ pip install --user SomePackage
   [...]
-  Requirement already satisfied (use --upgrade to upgrade)
-
-  $ pip install --user --upgrade SomePackage
-  [...]
   Requirement already up-to-date: SomePackage
 
   # force the install
@@ -657,7 +646,7 @@ You can then install from the archive like this::
 
     $ tempdir=$(mktemp -d /tmp/wheelhouse-XXXXX)
     $ (cd $tempdir; tar -xvf /path/to/bundled.tar.bz2)
-    $ pip install --force-reinstall --ignore-installed --upgrade --no-index --no-deps $tempdir/*
+    $ pip install --force-reinstall --ignore-installed --no-index --no-deps $tempdir/*
 
 Note that compiled packages are typically OS- and architecture-specific, so
 these archives are not necessarily portable across machines.
diff --git a/pip/commands/install.py b/pip/commands/install.py
index 28d30c59f7b..db2926799bc 100644
--- a/pip/commands/install.py
+++ b/pip/commands/install.py
@@ -67,9 +67,7 @@ def __init__(self, *args, **kw):
             metavar='dir',
             default=None,
             help='Install packages into <dir>. '
-                 'By default this will not replace existing files/folders in '
-                 '<dir>. Use --upgrade to replace existing packages in <dir> '
-                 'with new versions.'
+                 'This will not replace existing files/folders in <dir>.'
         )
 
         cmd_opts.add_option(
@@ -87,17 +85,14 @@ def __init__(self, *args, **kw):
             '-U', '--upgrade',
             dest='upgrade',
             action='store_true',
-            help='Upgrade all specified packages to the newest available '
-                 'version. This process is recursive regardless of whether '
-                 'a dependency is already satisfied.'
+            help='No-op option. Kept for backwards compatibility.'
         )
 
         cmd_opts.add_option(
             '--force-reinstall',
             dest='force_reinstall',
             action='store_true',
-            help='When upgrading, reinstall all packages even if they are '
-                 'already up-to-date.')
+            help='Reinstall all packages even if they are already up-to-date.')
 
         cmd_opts.add_option(
             '-I', '--ignore-installed',
@@ -268,7 +263,6 @@ def run(self, options, args):
                     build_dir=build_dir,
                     src_dir=options.src_dir,
                     download_dir=options.download_dir,
-                    upgrade=options.upgrade,
                     as_egg=options.as_egg,
                     ignore_installed=options.ignore_installed,
                     ignore_dependencies=options.ignore_dependencies,
@@ -368,26 +362,12 @@ def run(self, options, args):
                 for item in os.listdir(lib_dir):
                     target_item_dir = os.path.join(options.target_dir, item)
                     if os.path.exists(target_item_dir):
-                        if not options.upgrade:
-                            logger.warning(
-                                'Target directory %s already exists. Specify '
-                                '--upgrade to force replacement.',
-                                target_item_dir
-                            )
-                            continue
-                        if os.path.islink(target_item_dir):
-                            logger.warning(
-                                'Target directory %s already exists and is '
-                                'a link. Pip will not automatically replace '
-                                'links, please remove if replacement is '
-                                'desired.',
-                                target_item_dir
-                            )
-                            continue
-                        if os.path.isdir(target_item_dir):
-                            shutil.rmtree(target_item_dir)
-                        else:
-                            os.remove(target_item_dir)
+                        logger.warning(
+                            'Skipping target directory %s as it already '
+                            'exists.',
+                            target_item_dir
+                        )
+                        continue
 
                     shutil.move(
                         os.path.join(lib_dir, item),
diff --git a/pip/commands/wheel.py b/pip/commands/wheel.py
index 53f85e31b27..a8096196de1 100644
--- a/pip/commands/wheel.py
+++ b/pip/commands/wheel.py
@@ -107,18 +107,18 @@ def check_required_packages(self):
             "'pip wheel' requires the 'wheel' package. To fix this, run: "
             "pip install wheel"
         )
+
+        need_setuptools_message = (
+            "'pip wheel' requires setuptools >= 0.8 for dist-info support. "
+            "To fix this, run: pip install setuptools>=0.8"
+        )
         pkg_resources = import_or_raise(
             'pkg_resources',
             CommandError,
-            "'pip wheel' requires setuptools >= 0.8 for dist-info support."
-            " To fix this, run: pip install --upgrade setuptools"
+            need_setuptools_message
         )
         if not hasattr(pkg_resources, 'DistInfoDistribution'):
-            raise CommandError(
-                "'pip wheel' requires setuptools >= 0.8 for dist-info "
-                "support. To fix this, run: pip install --upgrade "
-                "setuptools"
-            )
+            raise CommandError(need_setuptools_message)
 
     def run(self, options, args):
         self.check_required_packages()
diff --git a/pip/req/req_set.py b/pip/req/req_set.py
index a4e6b0e161b..7f0e70a4aee 100644
--- a/pip/req/req_set.py
+++ b/pip/req/req_set.py
@@ -139,7 +139,7 @@ def prep_for_dist(self):
 
 class RequirementSet(object):
 
-    def __init__(self, build_dir, src_dir, download_dir, upgrade=False,
+    def __init__(self, build_dir, src_dir, download_dir,
                  ignore_installed=False, as_egg=False, target_dir=None,
                  ignore_dependencies=False, force_reinstall=False,
                  use_user_site=False, session=None, pycompile=True,
@@ -169,7 +169,6 @@ def __init__(self, build_dir, src_dir, download_dir, upgrade=False,
         # be combined if we're willing to have non-wheel archives present in
         # the wheelhouse output by 'pip wheel'.
         self.download_dir = download_dir
-        self.upgrade = upgrade
         self.ignore_installed = ignore_installed
         self.force_reinstall = force_reinstall
         self.requirements = Requirements()
@@ -241,6 +240,8 @@ def add_requirement(self, install_req, parent_req_name=None):
         install_req.use_user_site = self.use_user_site
         install_req.target_dir = self.target_dir
         install_req.pycompile = self.pycompile
+        install_req.is_direct = (parent_req_name is None)
+
         if not name:
             # url or path requirement w/o an egg fragment
             self.unnamed_requirements.append(install_req)
@@ -396,17 +397,20 @@ def _check_skip_installed(self, req_to_install, finder):
         # Check whether to upgrade/reinstall this req or not.
         req_to_install.check_if_exists()
         if req_to_install.satisfied_by:
-            skip_reason = 'satisfied (use --upgrade to upgrade)'
-            if self.upgrade:
-                best_installed = False
+            upgrade_allowed = req_to_install.is_direct
+
+            # Is the best version is installed.
+            best_installed = False
+
+            if upgrade_allowed:
                 # For link based requirements we have to pull the
                 # tree down and inspect to assess the version #, so
                 # its handled way down.
                 if not (self.force_reinstall or req_to_install.link):
                     try:
-                        finder.find_requirement(req_to_install, self.upgrade)
+                        finder.find_requirement(
+                            req_to_install, upgrade_allowed)
                     except BestVersionAlreadyInstalled:
-                        skip_reason = 'up-to-date'
                         best_installed = True
                     except DistributionNotFound:
                         # No distribution found, so we squash the
@@ -423,6 +427,17 @@ def _check_skip_installed(self, req_to_install, finder):
                         req_to_install.conflicts_with = \
                             req_to_install.satisfied_by
                     req_to_install.satisfied_by = None
+
+            # Figure out a nice message to say why we're skipping this.
+            if best_installed:
+                skip_reason = 'already up-to-date'
+            elif not upgrade_allowed:
+                # NOTE: Change this message if someday the upgrade strategy
+                #       changes.
+                skip_reason = 'not upgraded as not directly required'
+            else:
+                skip_reason = 'already satisfied'
+
             return skip_reason
         else:
             return None
@@ -443,6 +458,7 @@ def _prepare_file(self,
             return []
 
         req_to_install.prepared = True
+        upgrade_allowed = req_to_install.is_direct
 
         # ###################### #
         # # print log messages # #
@@ -463,7 +479,7 @@ def _prepare_file(self,
                     'req_to_install.satisfied_by is set to %r'
                     % (req_to_install.satisfied_by,))
                 logger.info(
-                    'Requirement already %s: %s', skip_reason,
+                    'Requirement %s: %s', skip_reason,
                     req_to_install)
             else:
                 if (req_to_install.link and
@@ -519,7 +535,7 @@ def _prepare_file(self,
                         % (req_to_install, req_to_install.source_dir)
                     )
                 req_to_install.populate_link(
-                    finder, self.upgrade, require_hashes)
+                    finder, upgrade_allowed, require_hashes)
                 # We can't hit this spot and have populate_link return None.
                 # req_to_install.satisfied_by is None here (because we're
                 # guarded) and upgrade has no impact except when satisfied_by
@@ -609,7 +625,7 @@ def _prepare_file(self,
                 if not self.ignore_installed:
                     req_to_install.check_if_exists()
                 if req_to_install.satisfied_by:
-                    if self.upgrade or self.ignore_installed:
+                    if upgrade_allowed or self.ignore_installed:
                         # don't uninstall conflict if user install and
                         # conflict is not user install
                         if not (self.use_user_site and not
@@ -620,8 +636,7 @@ def _prepare_file(self,
                         req_to_install.satisfied_by = None
                     else:
                         logger.info(
-                            'Requirement already satisfied (use '
-                            '--upgrade to upgrade): %s',
+                            'Requirement already satisfied: %s',
                             req_to_install,
                         )
 
diff --git a/pip/utils/outdated.py b/pip/utils/outdated.py
index 2164cc3cc2f..2bc65a56d8a 100644
--- a/pip/utils/outdated.py
+++ b/pip/utils/outdated.py
@@ -151,7 +151,7 @@ def pip_version_check(session):
             logger.warning(
                 "You are using pip version %s, however version %s is "
                 "available.\nYou should consider upgrading via the "
-                "'%s install --upgrade pip' command.",
+                "'%s install pip' command.",
                 pip_version, pypi_version, pip_cmd
             )
 
diff --git a/tests/data/packages/README.txt b/tests/data/packages/README.txt
index c36d77f1b0e..b2f61b5138c 100644
--- a/tests/data/packages/README.txt
+++ b/tests/data/packages/README.txt
@@ -108,3 +108,8 @@ requires_wheelbroken_upper
 --------------------------
 Requires wheelbroken and upper - used for testing implicit wheel building
 during install.
+
+require_simple-1.0.tar.gz
+------------------------
+contains "require_simple" package which requires simple>=2.0 - used for testing
+if dependencies are handled correctly.
diff --git a/tests/data/packages/require_simple-1.0.tar.gz b/tests/data/packages/require_simple-1.0.tar.gz
new file mode 100644
index 00000000000..c4eca04a783
Binary files /dev/null and b/tests/data/packages/require_simple-1.0.tar.gz differ
diff --git a/tests/functional/test_install.py b/tests/functional/test_install.py
index 1440f3335f9..8b088618b0e 100644
--- a/tests/functional/test_install.py
+++ b/tests/functional/test_install.py
@@ -527,33 +527,17 @@ def test_install_package_with_target(script):
         str(result)
     )
 
-    # Test repeated call without --upgrade, no files should have changed
+    # Test repeated call, no files should have changed
     result = script.pip_install_local(
         '-t', target_dir, "simple==1.0", expect_stderr=True,
     )
     assert not Path('scratch') / 'target' / 'simple' in result.files_updated
 
-    # Test upgrade call, check that new version is installed
-    result = script.pip_install_local('--upgrade', '-t',
-                                      target_dir, "simple==2.0")
-    assert Path('scratch') / 'target' / 'simple' in result.files_updated, (
-        str(result)
-    )
-    egg_folder = (
-        Path('scratch') / 'target' / 'simple-2.0-py%s.egg-info' % pyversion)
-    assert egg_folder in result.files_created, (
-        str(result)
-    )
-
-    # Test install and upgrade of single-module package
+    # Test install of single-module package
     result = script.pip_install_local('-t', target_dir, 'singlemodule==0.0.0')
     singlemodule_py = Path('scratch') / 'target' / 'singlemodule.py'
     assert singlemodule_py in result.files_created, str(result)
 
-    result = script.pip_install_local('-t', target_dir, 'singlemodule==0.0.1',
-                                      '--upgrade')
-    assert singlemodule_py in result.files_updated, str(result)
-
 
 def test_install_package_with_root(script, data):
     """
@@ -815,7 +799,7 @@ def test_install_upgrade_editable_depending_on_other_editable(script):
               version='0.1',
               install_requires=['pkga'])
     """))
-    script.pip('install', '--upgrade', '--editable', pkgb_path, '--no-index')
+    script.pip('install', '--editable', pkgb_path, '--no-index')
     result = script.pip('list', '--format=freeze')
     assert "pkgb==0.1" in result.stdout
 
@@ -1026,3 +1010,89 @@ def test_double_install_fail(script, data):
     msg = ("Double requirement given: pip==7.1.2 (already in pip==*, "
            "name='pip')")
     assert msg in result.stderr
+
+
+@pytest.mark.network
+def test_install_when_older_version_explicitly_passed_as_url(script):
+    """
+    When a file URL is passed, forcefully reinstall the package regardless
+    of whether it has a newer version already installed.
+
+    """
+    result = script.pip('install', 'INITools==0.3', expect_error=True)
+    assert script.site_packages / 'initools' in result.files_created, (
+        sorted(result.files_created.keys())
+    )
+    result2 = script.pip(
+        'install',
+        'https://pypi.python.org/packages/source/I/INITools/INITools-'
+        '0.2.tar.gz',
+        expect_error=True,
+    )
+    assert result2.files_updated, (
+        'INITools==0.2 was not installed over INITools==0.3 when explicitly '
+        'passed with a URL'
+    )
+
+
+def test_install_when_older_version_explicitly_passed_as_path(script, data):
+    """
+    When a file path is passed, forcefully reinstall the package regardless
+    of whether it has a newer version already installed.
+
+    """
+    result = script.pip_install_local('simple==3.0', expect_error=True)
+    assert script.site_packages / 'simple' in result.files_created, (
+        sorted(result.files_created.keys())
+    )
+    result2 = script.pip_install_local(
+        data.packages.join("simple-2.0.tar.gz"),
+        expect_error=True,
+    )
+    assert result2.files_updated, (
+        'simple==0.2 was not installed over simple==0.3 when explicitly '
+        'passed with a path'
+    )
+
+
+@pytest.mark.network
+def test_install_when_same_version_explicitly_passed_as_url(script):
+    """
+    When a file URL is passed, forcefully reinstall the package regardless
+    of whether it has a newer version already installed.
+
+    """
+    result = script.pip('install', 'INITools==0.3', expect_error=True)
+    assert script.site_packages / 'initools' in result.files_created, (
+        sorted(result.files_created.keys())
+    )
+    result2 = script.pip(
+        'install',
+        'https://pypi.python.org/packages/source/I/INITools/INITools-'
+        '0.3.tar.gz',
+        expect_error=True,
+    )
+    assert result2.files_updated, (
+        'INITools==0.3 was not installed over INITools==0.3 when explicitly '
+        'passed with a URL'
+    )
+
+
+def test_install_when_same_version_explicitly_passed_as_path(script, data):
+    """
+    When a file path is passed, forcefully reinstall the package regardless
+    of whether it has a newer version already installed.
+
+    """
+    result = script.pip_install_local('simple==3.0', expect_error=True)
+    assert script.site_packages / 'simple' in result.files_created, (
+        sorted(result.files_created.keys())
+    )
+    result2 = script.pip_install_local(
+        data.packages.join("simple-3.0.tar.gz"),
+        expect_error=True,
+    )
+    assert result2.files_updated, (
+        'simple==0.3 was not installed over simple==0.3 when explicitly '
+        'passed with a path'
+    )
diff --git a/tests/functional/test_install_upgrade.py b/tests/functional/test_install_upgrade.py
index f4a78f0ca7c..1ba25ce4a5d 100644
--- a/tests/functional/test_install_upgrade.py
+++ b/tests/functional/test_install_upgrade.py
@@ -11,17 +11,76 @@
 from tests.lib.local_repos import local_checkout
 
 
-def test_no_upgrade_unless_requested(script):
+def test_upgrade_by_default(script):
     """
-    No upgrade if not specifically requested.
+    It does upgrade if not specifically requested.
 
     """
     script.pip('install', 'INITools==0.1', expect_error=True)
     result = script.pip('install', 'INITools', expect_error=True)
-    assert not result.files_created, (
-        'pip install INITools upgraded when it should not have'
+    assert result.files_created, (
+        'pip install INITools did not upgrade when it should have'
+    )
+
+
+def test_does_not_upgrade_dependecies_if_existing_version_satisfies(script):
+    """
+    It doesn't upgrade a dependency if it already satisfies the requirements.
+
+    """
+    script.pip_install_local('simple==2.0', expect_error=True)
+    result = script.pip_install_local('require_simple', expect_error=True)
+
+    assert (
+        (script.site_packages / 'require_simple-1.0-py%s.egg-info' % pyversion)
+        not in result.files_deleted
+    ), "should have installed require_simple==1.0"
+    assert (
+        (script.site_packages / 'simple-2.0-py%s.egg-info' % pyversion)
+        not in result.files_deleted
+    ), "should not have uninstalled simple==2.0"
+
+
+def test_upgrade_dependecies_if_existing_version_does_not_satisfy(script):
+    """
+    It does upgrade a dependency if it already satisfies the requirements.
+
+    """
+    script.pip_install_local('simple==1.0', expect_error=True)
+    result = script.pip_install_local('require_simple', expect_error=True)
+
+    assert (
+        (script.site_packages / 'require_simple-1.0-py%s.egg-info' % pyversion)
+        not in result.files_deleted
+    ), "should have installed require_simple==1.0"
+    assert (
+        script.site_packages / 'simple-3.0-py%s.egg-info' %
+        pyversion in result.files_created
+    ), "should have installed simple==3.0"
+    assert (
+        script.site_packages / 'simple-1.0-py%s.egg-info' %
+        pyversion in result.files_deleted
+    ), "should have uninstalled simple==1.0"
+
+
+def test_upgrade_option_does_not_affect_behaviour(script):
+    """
+    It does not change behaviour on passing --upgrade.
+    """
+    script.pip_install_local('simple==2.0', expect_error=True)
+    result = script.pip_install_local(
+        'require_simple', '--upgrade', expect_error=True
     )
 
+    assert (
+        (script.site_packages / 'require_simple-1.0-py%s.egg-info' % pyversion)
+        not in result.files_deleted
+    ), "should have installed require_simple==1.0"
+    assert (
+        (script.site_packages / 'simple-2.0-py%s.egg-info' % pyversion)
+        not in result.files_deleted
+    ), "should not have uninstalled simple==2.0"
+
 
 @pytest.mark.network
 def test_upgrade_to_specific_version(script):
@@ -51,8 +110,8 @@ def test_upgrade_if_requested(script):
 
     """
     script.pip('install', 'INITools==0.1', expect_error=True)
-    result = script.pip('install', '--upgrade', 'INITools', expect_error=True)
-    assert result.files_created, 'pip install --upgrade did not upgrade'
+    result = script.pip('install', 'INITools', expect_error=True)
+    assert result.files_created, 'pip install did not upgrade'
     assert (
         script.site_packages / 'INITools-0.1-py%s.egg-info' %
         pyversion not in result.files_created
@@ -66,7 +125,7 @@ def test_upgrade_with_newest_already_installed(script, data):
     """
     script.pip('install', '-f', data.find_links, '--no-index', 'simple')
     result = script.pip(
-        'install', '--upgrade', '-f', data.find_links, '--no-index', 'simple'
+        'install', '-f', data.find_links, '--no-index', 'simple'
     )
     assert not result.files_created, 'simple upgraded when it should not have'
     assert 'already up-to-date' in result.stdout, result.stdout
@@ -83,7 +142,7 @@ def test_upgrade_force_reinstall_newest(script):
         sorted(result.files_created.keys())
     )
     result2 = script.pip(
-        'install', '--upgrade', '--force-reinstall', 'INITools'
+        'install', '--force-reinstall', 'INITools'
     )
     assert result2.files_updated, 'upgrade to INITools 0.3 failed'
     result3 = script.pip('uninstall', 'initools', '-y', expect_error=True)
@@ -130,8 +189,8 @@ def test_uninstall_before_upgrade_from_url(script):
 @pytest.mark.network
 def test_upgrade_to_same_version_from_url(script):
     """
-    When installing from a URL the same version that is already installed, no
-    need to uninstall and reinstall if --upgrade is not specified.
+    When installing from a URL the same version that is already installed,
+    ensure an uninstall and reinstall take place.
 
     """
     result = script.pip('install', 'INITools==0.3', expect_error=True)
@@ -144,7 +203,7 @@ def test_upgrade_to_same_version_from_url(script):
         '0.3.tar.gz',
         expect_error=True,
     )
-    assert not result2.files_updated, 'INITools 0.3 reinstalled same version'
+    assert result2.files_updated, 'INITools 0.3 did not reinstall same version'
     result3 = script.pip('uninstall', 'initools', '-y', expect_error=True)
     assert_all_changes(result, result3, [script.venv / 'build', 'cache'])
 
@@ -169,7 +228,7 @@ def test_upgrade_from_reqs_file(script):
         INITools
         """))
     script.pip(
-        'install', '--upgrade', '-r', script.scratch_path / 'test-req.txt'
+        'install', '-r', script.scratch_path / 'test-req.txt'
     )
     uninstall_result = script.pip(
         'uninstall', '-r', script.scratch_path / 'test-req.txt', '-y'
@@ -277,7 +336,7 @@ def test_upgrade_vcs_req_with_no_dists_found(script, tmpdir):
         tmpdir.join("cache"),
     )
     script.pip("install", req)
-    result = script.pip("install", "-U", req)
+    result = script.pip("install", req)
     assert not result.returncode
 
 
@@ -294,7 +353,7 @@ def test_upgrade_vcs_req_with_dist_found(script):
         )
     )
     script.pip("install", req, expect_stderr=True)
-    result = script.pip("install", "-U", req, expect_stderr=True)
+    result = script.pip("install", req, expect_stderr=True)
     assert "pypi.python.org" not in result.stdout, result.stdout
 
 
@@ -304,13 +363,18 @@ class TestUpgradeDistributeToSetuptools(object):
     allow distribute to conflict with setuptools, so that the following would
     work to upgrade distribute:
 
-     ``pip install -U  setuptools``
+     ``pip install -U setuptools``
 
     In pip7, the hacks were removed.  This test remains to at least confirm pip
     can upgrade distribute to setuptools using:
 
       ``pip install -U distribute``
 
+    In pip9, install started upgrading by default, thus removing the need to
+    pass -U:
+
+      ``pip install distribute``
+
     The reason this works is that a final version of distribute (v0.7.3) was
     released that is simple wrapper with:
 
@@ -354,7 +418,7 @@ def test_from_distribute_6_to_setuptools_7(
         )
         result = self.script.run(
             self.ve_bin / 'pip', 'install', '--no-index',
-            '--find-links=%s' % data.find_links, '-U', 'distribute',
+            '--find-links=%s' % data.find_links, 'distribute',
             expect_stderr=True if sys.version_info[:2] == (2, 6) else False,
         )
         assert (