Denso cabin filter out of wife's '08 Civic that I put in 2 years ago, ~10k miles. Yup, a mouse got to it... and another car we have parked outside. My guess is lack of use of both cars, mostly home due to Covid-19.
Still surprisingly dark, I think I'm going to start replacing it yearly as its super easy and the filter is <$10. Unlike my W124, which involves partial removal of windshield cowling.
Replaced with a Wix 24815.