k&n drop in filter

[billssr5]

Those intervals seem extended

maybe, im close to 30k miles now 99% street use and is still serviceable IMO, could be different if you offroad or are in dusty desert regions then I would guess at 10k-15k intervals

 

[OR17TRD]

I'd say check it at each oil change knock the big stuff off and when you hold it up and it's harder to see light through it then replace. The longer you go the engines performance will suffer.

 

[billssr5]

heres a couples pictures of my cheapo Chinese EBAY filter at 25k miles not too bad just black grit, seems to be doing the job for $11.99 plus cabin filter deal.