pretty average driving conditions... mostly pavement. a guy told me they need to be cleaned every couple months?

 

I run a pre filter on mine and about 15k-20k a year. I clean it once a year. the other truck needs to be cleaned more often as its over loaded with dirt quicker. I guess clean it when its overly dirty or starting to get dry.

 

I clean mine every quarter but the way to tell is if you can barely hear the turbo at low RPM's, this is a good tip to clean the filter.

 

Hmmm do work a little better when they kinda get dirty? Mine looks bad, but can still hear the turbo. I have about 20K on it.