> We do - they are just a lot bigger.

Yeah, of course, but I am not aware of any regular car which comes stock with such filters.

The point was really that lasting 22k miles longer than stock would be an unrealistic improvement for a filter for a normal car.

> You should replace the oil filter when it is no longer filtering.

I was specifically referring to manufacturer recommendations. Of course they're conservative, they also have to account for engine wear.

And yes, you are right that ideally you'd test. Although testing the filter from what I've seen is destructive, and there's a nontrivial turnaround time.

I'd disagree that following manufacturer recommendations is a waste of money though. As you say, testing is _more_ expensive. Engine damage is even more expensive. Replacing the filter on schedule is the economical choice.

It might be strictly a waste of resources, but that's a separate concern.