diff --git a/pandas/core/array_algos/take.py b/pandas/core/array_algos/take.py
index 8ea70e2694d92..ac674e31586e7 100644
--- a/pandas/core/array_algos/take.py
+++ b/pandas/core/array_algos/take.py
@@ -66,8 +66,7 @@ def take_nd(
     """
     Specialized Cython take which sets NaN values in one pass
 
-    This dispatches to ``take`` defined on ExtensionArrays. It does not
-    currently dispatch to ``SparseArray.take`` for sparse ``arr``.
+    This dispatches to ``take`` defined on ExtensionArrays.
 
     Note: this function assumes that the indexer is a valid(ated) indexer with
     no out of bound indices.
diff --git a/pandas/core/arrays/base.py b/pandas/core/arrays/base.py
index 3a6db34b0e8b5..3827b5b5d40b2 100644
--- a/pandas/core/arrays/base.py
+++ b/pandas/core/arrays/base.py
@@ -2042,6 +2042,7 @@ def _where(self, mask: npt.NDArray[np.bool_], value) -> Self:
         result[~mask] = val
         return result
 
+    # TODO(3.0): this can be removed once GH#33302 deprecation is enforced
     def _fill_mask_inplace(
         self, method: str, limit: int | None, mask: npt.NDArray[np.bool_]
     ) -> None:
diff --git a/pandas/core/arrays/categorical.py b/pandas/core/arrays/categorical.py
index aefc94ebd665c..dae0fb7782791 100644
--- a/pandas/core/arrays/categorical.py
+++ b/pandas/core/arrays/categorical.py
@@ -2898,17 +2898,15 @@ def _delegate_method(self, name: str, *args, **kwargs):
 # utility routines
 
 
-def _get_codes_for_values(values, categories: Index) -> np.ndarray:
+def _get_codes_for_values(
+    values: Index | Series | ExtensionArray | np.ndarray,
+    categories: Index,
+) -> np.ndarray:
     """
     utility routine to turn values into codes given the specified categories
 
     If `values` is known to be a Categorical, use recode_for_categories instead.
     """
-    if values.ndim > 1:
-        flat = values.ravel()
-        codes = _get_codes_for_values(flat, categories)
-        return codes.reshape(values.shape)
-
     codes = categories.get_indexer_for(values)
     return coerce_indexer_dtype(codes, categories)
 
diff --git a/pandas/core/config_init.py b/pandas/core/config_init.py
index 27e9bf8958ab0..0e857626b5697 100644
--- a/pandas/core/config_init.py
+++ b/pandas/core/config_init.py
@@ -420,6 +420,7 @@ def is_terminal() -> bool:
 
 
 def use_inf_as_na_cb(key) -> None:
+    # TODO(3.0): enforcing this deprecation will close GH#52501
     from pandas.core.dtypes.missing import _use_inf_as_na
 
     _use_inf_as_na(key)
diff --git a/pandas/core/dtypes/cast.py b/pandas/core/dtypes/cast.py
index 657cbce40087a..aa228191adc62 100644
--- a/pandas/core/dtypes/cast.py
+++ b/pandas/core/dtypes/cast.py
@@ -1707,8 +1707,6 @@ def can_hold_element(arr: ArrayLike, element: Any) -> bool:
                 arr._validate_setitem_value(element)
                 return True
             except (ValueError, TypeError):
-                # TODO: re-use _catch_deprecated_value_error to ensure we are
-                #  strict about what exceptions we allow through here.
                 return False
 
         # This is technically incorrect, but maintains the behavior of
diff --git a/pandas/core/dtypes/dtypes.py b/pandas/core/dtypes/dtypes.py
index a9618963e0a51..59939057d4b37 100644
--- a/pandas/core/dtypes/dtypes.py
+++ b/pandas/core/dtypes/dtypes.py
@@ -985,6 +985,7 @@ def __new__(cls, freq):
 
         if isinstance(freq, BDay):
             # GH#53446
+            # TODO(3.0): enforcing this will close GH#10575
             warnings.warn(
                 "PeriodDtype[B] is deprecated and will be removed in a future "
                 "version. Use a DatetimeIndex with freq='B' instead",
diff --git a/pandas/core/generic.py b/pandas/core/generic.py
index 7da41b890598d..32069575c807b 100644
--- a/pandas/core/generic.py
+++ b/pandas/core/generic.py
@@ -255,8 +255,6 @@ class NDFrame(PandasObject, indexing.IndexingMixin):
         "_is_copy",
         "_name",
         "_metadata",
-        "__array_struct__",
-        "__array_interface__",
         "_flags",
     ]
     _internal_names_set: set[str] = set(_internal_names)
@@ -6970,6 +6968,9 @@ def _pad_or_backfill(
         method = clean_fill_method(method)
 
         if not self._mgr.is_single_block and axis == 1:
+            # e.g. test_align_fill_method
+            # TODO(3.0): once downcast is removed, we can do the .T
+            #  in all axis=1 cases, and remove axis kward from mgr.pad_or_backfill.
             if inplace:
                 raise NotImplementedError()
             result = self.T._pad_or_backfill(method=method, limit=limit).T
diff --git a/pandas/core/groupby/grouper.py b/pandas/core/groupby/grouper.py
index ea92fbae9566d..95cb114c1472a 100644
--- a/pandas/core/groupby/grouper.py
+++ b/pandas/core/groupby/grouper.py
@@ -441,6 +441,8 @@ def indexer(self):
     @final
     @property
     def obj(self):
+        # TODO(3.0): enforcing these deprecations on Grouper should close
+        #  GH#25564, GH#41930
         warnings.warn(
             f"{type(self).__name__}.obj is deprecated and will be removed "
             "in a future version. Use GroupBy.indexer instead.",
diff --git a/pandas/core/indexes/base.py b/pandas/core/indexes/base.py
index 796aadf9e4061..93b99b7647fc0 100644
--- a/pandas/core/indexes/base.py
+++ b/pandas/core/indexes/base.py
@@ -3782,9 +3782,15 @@ def get_loc(self, key):
             self._check_indexing_error(key)
             raise
 
-    _index_shared_docs[
-        "get_indexer"
-    ] = """
+    @final
+    def get_indexer(
+        self,
+        target,
+        method: ReindexMethod | None = None,
+        limit: int | None = None,
+        tolerance=None,
+    ) -> npt.NDArray[np.intp]:
+        """
         Compute indexer and mask for new index given the current index.
 
         The indexer should be then used as an input to ndarray.take to align the
@@ -3792,7 +3798,7 @@ def get_loc(self, key):
 
         Parameters
         ----------
-        target : %(target_klass)s
+        target : Index
         method : {None, 'pad'/'ffill', 'backfill'/'bfill', 'nearest'}, optional
             * default: exact matches only.
             * pad / ffill: find the PREVIOUS index value if no exact match.
@@ -3819,7 +3825,7 @@ def get_loc(self, key):
             Integers from 0 to n - 1 indicating that the index at these
             positions matches the corresponding target values. Missing values
             in the target are marked by -1.
-        %(raises_section)s
+
         Notes
         -----
         Returns -1 for unmatched values, for further explanation see the
@@ -3834,16 +3840,6 @@ def get_loc(self, key):
         Notice that the return value is an array of locations in ``index``
         and ``x`` is marked by -1, as it is not in ``index``.
         """
-
-    @Appender(_index_shared_docs["get_indexer"] % _index_doc_kwargs)
-    @final
-    def get_indexer(
-        self,
-        target,
-        method: ReindexMethod | None = None,
-        limit: int | None = None,
-        tolerance=None,
-    ) -> npt.NDArray[np.intp]:
         method = clean_reindex_fill_method(method)
         orig_target = target
         target = self._maybe_cast_listlike_indexer(target)
@@ -3898,7 +3894,7 @@ def get_indexer(
 
             return ensure_platform_int(indexer)
 
-        pself, ptarget = self._maybe_promote(target)
+        pself, ptarget = self._maybe_downcast_for_indexing(target)
         if pself is not self or ptarget is not target:
             return pself.get_indexer(
                 ptarget, method=method, limit=limit, tolerance=tolerance
@@ -4582,7 +4578,7 @@ def join(
 
         if not self._is_multi and not other._is_multi:
             # We have specific handling for MultiIndex below
-            pself, pother = self._maybe_promote(other)
+            pself, pother = self._maybe_downcast_for_indexing(other)
             if pself is not self or pother is not other:
                 return pself.join(
                     pother, how=how, level=level, return_indexers=True, sort=sort
@@ -6046,7 +6042,7 @@ def get_indexer_non_unique(
             #  that can be matched to Interval scalars.
             return self._get_indexer_non_comparable(target, method=None, unique=False)
 
-        pself, ptarget = self._maybe_promote(target)
+        pself, ptarget = self._maybe_downcast_for_indexing(target)
         if pself is not self or ptarget is not target:
             return pself.get_indexer_non_unique(ptarget)
 
@@ -6062,8 +6058,8 @@ def get_indexer_non_unique(
         # TODO: get_indexer has fastpaths for both Categorical-self and
         #  Categorical-target. Can we do something similar here?
 
-        # Note: _maybe_promote ensures we never get here with MultiIndex
-        #  self and non-Multi target
+        # Note: _maybe_downcast_for_indexing ensures we never get here
+        #  with MultiIndex self and non-Multi target
         tgt_values = target._get_engine_target()
         if self._is_multi and target._is_multi:
             engine = self._engine
@@ -6237,7 +6233,7 @@ def _index_as_unique(self) -> bool:
     _requires_unique_msg = "Reindexing only valid with uniquely valued Index objects"
 
     @final
-    def _maybe_promote(self, other: Index) -> tuple[Index, Index]:
+    def _maybe_downcast_for_indexing(self, other: Index) -> tuple[Index, Index]:
         """
         When dealing with an object-dtype Index and a non-object Index, see
         if we can upcast the object-dtype one to improve performance.
@@ -6278,7 +6274,7 @@ def _maybe_promote(self, other: Index) -> tuple[Index, Index]:
 
         if not is_object_dtype(self.dtype) and is_object_dtype(other.dtype):
             # Reverse op so we dont need to re-implement on the subclasses
-            other, self = other._maybe_promote(self)
+            other, self = other._maybe_downcast_for_indexing(self)
 
         return self, other
 
diff --git a/pandas/core/internals/blocks.py b/pandas/core/internals/blocks.py
index eca0df67ff054..ffaeef14e42a5 100644
--- a/pandas/core/internals/blocks.py
+++ b/pandas/core/internals/blocks.py
@@ -27,7 +27,6 @@
     BlockValuesRefs,
 )
 from pandas._libs.missing import NA
-from pandas._libs.tslibs import IncompatibleFrequency
 from pandas._typing import (
     ArrayLike,
     AxisInt,
@@ -1731,9 +1730,7 @@ def setitem(self, indexer, value, using_cow: bool = False):
 
         try:
             values[indexer] = value
-        except (ValueError, TypeError) as err:
-            _catch_deprecated_value_error(err)
-
+        except (ValueError, TypeError):
             if isinstance(self.dtype, IntervalDtype):
                 # see TestSetitemFloatIntervalWithIntIntervalValues
                 nb = self.coerce_to_target_dtype(orig_value, warn_on_upcast=True)
@@ -1776,9 +1773,7 @@ def where(
 
         try:
             res_values = arr._where(cond, other).T
-        except (ValueError, TypeError) as err:
-            _catch_deprecated_value_error(err)
-
+        except (ValueError, TypeError):
             if self.ndim == 1 or self.shape[0] == 1:
                 if isinstance(self.dtype, IntervalDtype):
                     # TestSetitemFloatIntervalWithIntIntervalValues
@@ -1847,9 +1842,7 @@ def putmask(self, mask, new, using_cow: bool = False) -> list[Block]:
         try:
             # Caller is responsible for ensuring matching lengths
             values._putmask(mask, new)
-        except (TypeError, ValueError) as err:
-            _catch_deprecated_value_error(err)
-
+        except (TypeError, ValueError):
             if self.ndim == 1 or self.shape[0] == 1:
                 if isinstance(self.dtype, IntervalDtype):
                     # Discussion about what we want to support in the general
@@ -2256,19 +2249,6 @@ def is_view(self) -> bool:
         return self.values._ndarray.base is not None
 
 
-def _catch_deprecated_value_error(err: Exception) -> None:
-    """
-    We catch ValueError for now, but only a specific one raised by DatetimeArray
-    which will no longer be raised in version 2.0.
-    """
-    if isinstance(err, ValueError):
-        if isinstance(err, IncompatibleFrequency):
-            pass
-        elif "'value.closed' is" in str(err):
-            # IntervalDtype mismatched 'closed'
-            pass
-
-
 class DatetimeLikeBlock(NDArrayBackedExtensionBlock):
     """Block for datetime64[ns], timedelta64[ns]."""
 
diff --git a/pandas/core/series.py b/pandas/core/series.py
index 564c799d7ab66..9a934217ed5c1 100644
--- a/pandas/core/series.py
+++ b/pandas/core/series.py
@@ -3985,6 +3985,8 @@ def argsort(
         mask = isna(values)
 
         if mask.any():
+            # TODO(3.0): once this deprecation is enforced we can call
+            #  self.array.argsort directly, which will close GH#43840
             warnings.warn(
                 "The behavior of Series.argsort in the presence of NA values is "
                 "deprecated. In a future version, NA values will be ordered "
@@ -5199,6 +5201,7 @@ def info(
             show_counts=show_counts,
         )
 
+    # TODO(3.0): this can be removed once GH#33302 deprecation is enforced
     def _replace_single(self, to_replace, method: str, inplace: bool, limit):
         """
         Replaces values in a Series using the fill method specified when no
diff --git a/pandas/tests/arrays/string_/test_string.py b/pandas/tests/arrays/string_/test_string.py
index de93e89ecacd5..1476ef87f4666 100644
--- a/pandas/tests/arrays/string_/test_string.py
+++ b/pandas/tests/arrays/string_/test_string.py
@@ -94,6 +94,14 @@ def test_astype_roundtrip(dtype):
     result = casted.astype("datetime64[ns]")
     tm.assert_series_equal(result, ser)
 
+    # GH#38509 same thing for timedelta64
+    ser2 = ser - ser.iloc[-1]
+    casted2 = ser2.astype(dtype)
+    assert is_dtype_equal(casted2.dtype, dtype)
+
+    result2 = casted2.astype(ser2.dtype)
+    tm.assert_series_equal(result2, ser2)
+
 
 def test_add(dtype):
     a = pd.Series(["a", "b", "c", None, None], dtype=dtype)
diff --git a/pandas/tests/extension/base/reduce.py b/pandas/tests/extension/base/reduce.py
index 9b56b10681e15..4edbcacffe6af 100644
--- a/pandas/tests/extension/base/reduce.py
+++ b/pandas/tests/extension/base/reduce.py
@@ -83,6 +83,7 @@ def test_reduce_series_boolean(self, data, all_boolean_reductions, skipna):
         ser = pd.Series(data)
 
         if not self._supports_reduction(ser, op_name):
+            # TODO: the message being checked here isn't actually checking anything
             msg = (
                 "[Cc]annot perform|Categorical is not ordered for operation|"
                 "does not support reduction|"
@@ -101,6 +102,7 @@ def test_reduce_series_numeric(self, data, all_numeric_reductions, skipna):
         ser = pd.Series(data)
 
         if not self._supports_reduction(ser, op_name):
+            # TODO: the message being checked here isn't actually checking anything
             msg = (
                 "[Cc]annot perform|Categorical is not ordered for operation|"
                 "does not support reduction|"
diff --git a/pandas/tests/extension/date/array.py b/pandas/tests/extension/date/array.py
index 39accd6d223a7..2306f5974ba18 100644
--- a/pandas/tests/extension/date/array.py
+++ b/pandas/tests/extension/date/array.py
@@ -176,9 +176,13 @@ def isna(self) -> np.ndarray:
     @classmethod
     def _from_sequence(cls, scalars, *, dtype: Dtype | None = None, copy=False):
         if isinstance(scalars, dt.date):
-            pass
+            raise TypeError
         elif isinstance(scalars, DateArray):
-            pass
+            if dtype is not None:
+                return scalars.astype(dtype, copy=copy)
+            if copy:
+                return scalars.copy()
+            return scalars[:]
         elif isinstance(scalars, np.ndarray):
             scalars = scalars.astype("U10")  # 10 chars for yyyy-mm-dd
             return DateArray(scalars)
diff --git a/pandas/tests/extension/test_sparse.py b/pandas/tests/extension/test_sparse.py
index 01448a2f83f75..7330e03a57daf 100644
--- a/pandas/tests/extension/test_sparse.py
+++ b/pandas/tests/extension/test_sparse.py
@@ -220,8 +220,10 @@ def test_fillna_no_op_returns_copy(self, data, request):
         super().test_fillna_no_op_returns_copy(data)
 
     @pytest.mark.xfail(reason="Unsupported")
-    def test_fillna_series(self):
+    def test_fillna_series(self, data_missing):
         # this one looks doable.
+        # TODO: this fails bc we do not pass through data_missing. If we did,
+        #  the 0-fill case would xpass
         super().test_fillna_series()
 
     def test_fillna_frame(self, data_missing):
@@ -349,7 +351,9 @@ def test_map_raises(self, data, na_action):
 
 class TestCasting(BaseSparseTests, base.BaseCastingTests):
     @pytest.mark.xfail(raises=TypeError, reason="no sparse StringDtype")
-    def test_astype_string(self, data):
+    def test_astype_string(self, data, nullable_string_dtype):
+        # TODO: this fails bc we do not pass through nullable_string_dtype;
+        #  If we did, the 0-cases would xpass
         super().test_astype_string(data)
 
 
diff --git a/pandas/tests/extension/test_string.py b/pandas/tests/extension/test_string.py
index 8268de9a47f11..00e5e411bd0ed 100644
--- a/pandas/tests/extension/test_string.py
+++ b/pandas/tests/extension/test_string.py
@@ -201,7 +201,7 @@ def test_groupby_extension_apply(self, data_for_grouping, groupby_apply_op):
 
 class Test2DCompat(base.Dim2CompatTests):
     @pytest.fixture(autouse=True)
-    def arrow_not_supported(self, data, request):
+    def arrow_not_supported(self, data):
         if isinstance(data, ArrowStringArray):
             pytest.skip(reason="2D support not implemented for ArrowStringArray")
 
diff --git a/pandas/tests/series/methods/test_reindex.py b/pandas/tests/series/methods/test_reindex.py
index 2ab1cd13a31d8..bce7d2d554004 100644
--- a/pandas/tests/series/methods/test_reindex.py
+++ b/pandas/tests/series/methods/test_reindex.py
@@ -25,12 +25,7 @@
 def test_reindex(datetime_series, string_series):
     identity = string_series.reindex(string_series.index)
 
-    # __array_interface__ is not defined for older numpies
-    # and on some pythons
-    try:
-        assert np.may_share_memory(string_series.index, identity.index)
-    except AttributeError:
-        pass
+    assert np.may_share_memory(string_series.index, identity.index)
 
     assert identity.index.is_(string_series.index)
     assert identity.index.identical(string_series.index)
diff --git a/pandas/tests/series/test_arithmetic.py b/pandas/tests/series/test_arithmetic.py
index 80fd2fd7c0a06..44121cb5f784f 100644
--- a/pandas/tests/series/test_arithmetic.py
+++ b/pandas/tests/series/test_arithmetic.py
@@ -777,7 +777,7 @@ class TestNamePreservation:
     @pytest.mark.parametrize("box", [list, tuple, np.array, Index, Series, pd.array])
     @pytest.mark.parametrize("flex", [True, False])
     def test_series_ops_name_retention(self, flex, box, names, all_binary_operators):
-        # GH#33930 consistent name renteiton
+        # GH#33930 consistent name-retention
         op = all_binary_operators
 
         left = Series(range(10), name=names[0])