Show cache age instead of update date

src/_pytest/stepwise.py

@@ -2,6 +2,7 @@
 
 import dataclasses
 from datetime import datetime
+from datetime import timedelta
 from typing import Any
 from typing import TYPE_CHECKING
 
@@ -159,8 +160,11 @@ def pytest_collection_modifyitems(
         if failed_index is None:
             self.report_status.append("previously failed test not found, not skipping.")
         else:
+            cache_age = datetime.now() - self.cached_info.last_cache_date
+            # Round up to avoid showing microseconds.
+            cache_age = timedelta(seconds=int(cache_age.total_seconds()))
             self.report_status.append(
-                f"skipping {failed_index} already passed items (cache from {self.cached_info.last_cache_date},"
+                f"skipping {failed_index} already passed items (cache from {cache_age} ago,"
                 f" use --sw-reset to discard)."
             )
             deselected = items[:failed_index]

testing/test_stepwise.py

@@ -117,7 +117,7 @@ def test_data(expected):
     result = pytester.runpytest("-v", "--stepwise")
     result.stdout.fnmatch_lines(
         [
-            "stepwise: skipping 4 already passed items (cache from *, use --sw-reset to discard).",
+            "stepwise: skipping 4 already passed items (cache from * ago, use --sw-reset to discard).",
             "*1 failed, 4 deselected*",
         ]
     )