flip cache flag to True; changed to_dateime docstring

Author: anmyachev

doc/source/whatsnew/v0.25.0.rst

@@ -219,6 +219,7 @@ Other API Changes
 - Comparing :class:`Timestamp` with unsupported objects now returns :py:obj:`NotImplemented` instead of raising ``TypeError``. This implies that unsupported rich comparisons are delegated to the other object, and are now consistent with Python 3 behavior for ``datetime`` objects (:issue:`24011`)
 - Bug in :meth:`DatetimeIndex.snap` which didn't preserving the ``name`` of the input :class:`Index` (:issue:`25575`)
 - Added ``cache_dates`` parameter to :meth:`read_csv`, which allows to cache unique dates when they are parsed (:issue:`25990`)
+  Changed default value of `cache` parameter in :meth:`to_datetime` from False to True
 
 .. _whatsnew_0250.deprecations:
 

pandas/core/tools/datetimes.py

@@ -402,7 +402,7 @@ def _adjust_to_origin(arg, origin, unit):
 def to_datetime(arg, errors='raise', dayfirst=False, yearfirst=False,
                 utc=None, box=True, format=None, exact=True,
                 unit=None, infer_datetime_format=False, origin='unix',
-                cache=False):
+                cache=True):
     """
     Convert argument to datetime.
 
@@ -483,12 +483,12 @@ def to_datetime(arg, errors='raise', dayfirst=False, yearfirst=False,
           origin.
 
         .. versionadded:: 0.20.0
-    cache : boolean, default False
+    cache : boolean, default True
         If True, use a cache of unique, converted dates to apply the datetime
         conversion. May produce significant speed-up when parsing duplicate
         date strings, especially ones with timezone offsets.
 
-        .. versionadded:: 0.23.0
+        .. versionchanged:: 0.25.0
 
     Returns
     -------