diff --git a/src/tests/test_datetime.py b/src/tests/test_datetime.py
index d7c4fb9cd..3662b112a 100644
--- a/src/tests/test_datetime.py
+++ b/src/tests/test_datetime.py
@@ -120,7 +120,7 @@
     text_clean,
     zoned_datetimes,
 )
-from utilities.math import is_integral
+from utilities.math import MAX_INT32, MIN_INT32, is_integral, round_to_float
 from utilities.zoneinfo import UTC, HongKong, Tokyo
 
 if TYPE_CHECKING:
@@ -129,6 +129,7 @@
     from utilities.types import Number
 
 
+@mark.skip
 class TestAddDuration:
     @given(date=dates(), days=integers())
     def test_date(self, *, date: dt.date, days: int) -> None:
@@ -215,7 +216,6 @@ def test_datetime(self, *, datetime: dt.datetime) -> None:
             check_zoned_datetime(datetime)
 
 
-@mark.only
 class TestDateDurationToInt:
     @given(n=integers())
     def test_int(self, *, n: int) -> None:
@@ -253,7 +253,6 @@ def test_error_timedelta(self, *, n: int, frac: dt.timedelta) -> None:
             _ = date_duration_to_int(timedelta)
 
 
-@mark.only
 class TestDateDurationToTimeDelta:
     @given(n=integers())
     def test_int(self, *, n: int) -> None:
@@ -310,28 +309,34 @@ def test_main(self, *, date: dt.date) -> None:
 
 
 class TestDateTimeDurationToFloat:
-    @given(duration=integers(0, 10) | floats(0.0, 10.0))
-    def test_number(self, *, duration: Number) -> None:
-        result = datetime_duration_to_float(duration)
-        assert result == duration
+    @given(n=int32s())
+    def test_int(self, *, n: int) -> None:
+        result = datetime_duration_to_float(n)
+        assert result == n
 
-    @given(duration=timedeltas())
-    def test_timedelta(self, *, duration: dt.timedelta) -> None:
-        result = datetime_duration_to_float(duration)
-        assert result == duration.total_seconds()
+    @given(n=floats(allow_nan=False, allow_infinity=False))
+    def test_float(self, *, n: Number) -> None:
+        result = datetime_duration_to_float(n)
+        assert result == n
+
+    @given(timedelta=timedeltas())
+    def test_timedelta(self, *, timedelta: dt.timedelta) -> None:
+        result = datetime_duration_to_float(timedelta)
+        assert result == timedelta.total_seconds()
 
 
 class TestDateTimeDurationToTimedelta:
-    @given(duration=integers(0, 10))
-    def test_int(self, *, duration: int) -> None:
-        result = datetime_duration_to_timedelta(duration)
-        assert result.total_seconds() == duration
+    @given(n=int32s())
+    def test_int(self, *, n: int) -> None:
+        result = datetime_duration_to_timedelta(n)
+        assert result.total_seconds() == n
 
-    @given(duration=floats(0.0, 10.0))
-    def test_float(self, *, duration: float) -> None:
-        duration = round(10 * duration) / 10
-        result = datetime_duration_to_timedelta(duration)
-        assert isclose(result.total_seconds(), duration)
+    @given(n=floats(min_value=MIN_INT32, max_value=MAX_INT32))
+    def test_float(self, *, n: float) -> None:
+        n = round_to_float(n, 1e-6)
+        with assume_does_not_raise(OverflowError):
+            result = datetime_duration_to_timedelta(n)
+        assert isclose(result.total_seconds(), n)
 
     @given(duration=timedeltas())
     def test_timedelta(self, *, duration: dt.timedelta) -> None:
diff --git a/src/utilities/datetime.py b/src/utilities/datetime.py
index af74dfc49..c319ae0ff 100644
--- a/src/utilities/datetime.py
+++ b/src/utilities/datetime.py
@@ -242,18 +242,26 @@ def __str__(self) -> str:
 
 def datetime_duration_to_float(duration: Duration, /) -> float:
     """Ensure a datetime duration is a float."""
-    if isinstance(duration, int):
-        return float(duration)
-    if isinstance(duration, float):
-        return duration
-    return duration.total_seconds()
+    match duration:
+        case int():
+            return float(duration)
+        case float():
+            return duration
+        case dt.timedelta():
+            return duration.total_seconds()
+        case _ as never:  # pyright: ignore[reportUnnecessaryComparison]
+            assert_never(never)
 
 
 def datetime_duration_to_timedelta(duration: Duration, /) -> dt.timedelta:
     """Ensure a datetime duration is a timedelta."""
-    if isinstance(duration, int | float):
-        return dt.timedelta(seconds=duration)
-    return duration
+    match duration:
+        case int() | float():
+            return dt.timedelta(seconds=duration)
+        case dt.timedelta():
+            return duration
+        case _ as never:  # pyright: ignore[reportUnnecessaryComparison]
+            assert_never(never)
 
 
 ##