>don't know shit about car maintenance/repair
>always replace my own engine and cabine air filter anyway
>once let it go for an entire year and it didn't look visibly dirty
these things never look dirty. they never look stained or coated in dust, at best there are some tiny leaves or a single wasp stuck in the ridges

is this shit a scam? I'm feeling the same way about my own central hvac filter, I wait another month longer than I'm supposed to and there is barely and dust or hair stuck to it