How often you should change it really depends upon the driving conditions. If you do a lot of driving in dusty conditions you might need to change it fairly often and if you do most of your driving on pavement you might not need to change it for years.
Me personally, I replace the filter every spring. Most of my driving is done on pavement and we have winter from November-March, so dust really isnt much of an issue.

 

every 30k or when dirty.


This 30k the filter wasn't dirty.

We went with a purolator last time.. I think it lets too much dirt through. The orginal motorcraft one was filthy by 30k miles. This purolator isn't even dirty at all.


Probably go with a WIX (carquest blue) this time around since I get a good discount at carquest.

 

I have an AEM Dryflow (oiless) panel filter, so basically, I have a new filter every oil change (10,000 km's). It doesn't take long to clean the AEM, so I might as well clean it every oil change.

Prior to that, I'd usually go at least 20,000 km's before changing the OEM paper filter. I do roughly 25,000 km's per year.

 

Wow, to be honest, air filters really never need to be changed often. The worst case scenario for an air filter is that it may get dirty enough to start restricting air flow, but it will never stop filtering properly. Actually, when filters get dirty (Air, Oil, Hydraulic), they actually filter BETTER, but you must get concerned about Pressure drop, and lack of Volume flow, specifically in air filters. This would be only noticed in WOT conditions. Think about extremely old fuel filters, the most common symptom is power loss at very open throttle conditions, such as pulling a trailer up a steep highway grade, that's because it just can't pass the flow, but what it is passing is clean. The filtered matter stuck on the filtering media actually acts as a filtering media itself....sounds funny, but it's true. This is actually the way electric power generation water (Condensate) filters work. Hey, don't get me wrong, there is nothing wrong with changing your filters, and following your owners manual recommendations, but swapping them out frequently has absolutely no benefit to your machine.

 

buy a K & N from any parts store. then get a "recharge kit" wash it out and re oil it every 4 months and you wont ever have to worry.

 

K&N states once a year on cleaning. I never had good luck with it and always worried about the MAF - No matter how lightly oiled that filter was , it always contaminated the MAF and performance suffered. A dry element is 10 times better since I swapped back over to that . Been running a WIX for awhile now without a MAF issue. With a K&N , I could always tell when it was screwing the MAF up. It misted the wires and that made them a dust magnet.

 

X 2!! Even if you are gonna go K&N, four months is waaaaaay too excessive. That filter is designed to have a layer of gunk entrapped in the oil to function proplerly. And as mentioned, the oil will get on the MAF sensor.

I swapped out my K&N as soon as Amsoil came out with a universal filter to replace the filter on my FIPK...I cleaned the MAF when I swapped filters and immediately noticed improved idle!! I will not go back to an oil type filter when there are sensors involved.