How often do you check or replace your air filter ?

[oil pan 4]

I have a filter minder now. I'll check it every oil change and replace it the 2nd time when it hits 10'' H2O.

 

[Jetronic]

Leave it in there until you want to change it. 20k miles if you're in a dusty area, 40k otherwise.

Those of you blowing, vacuuming, or banging out your filters are doing nothing productive. Neither is "inspecting" the filter. They don't become spontaneously clogged.

I once found a filter housing brimfull of walnuts upon inspection, so I beg to differ.