Frailties of the 172?

[Oracle427]

Not sure why you would have oil leaks, but yes the filter is changed with the oil change.

[AKar]

In real airplanes, any abnormal oil leakage is quite obvious even for an untrained eye. While the lines should be checked visually every 50 hours or so, any leak likely gets noticed - should get noticed! - way before the scheduled check unless it occurs just before it.

-Esa

[jsbrewster1]

In this case, it always seems to happen right after the oil and filter change, it doesn't seem to be random, though maybe it is and just coincidence.