I like to get 10,000 miles out of a filter. i try to find an oversized one. for instance, Edge and Mobil EP are suposedly good for 15,000 miles, and they don't say on the bottle that you have to change your filter more often, so i think a filter is probably good for up to 15,ooo miles. however, i would not push it with some of the very tiny filters they have now, or if the engine is in bad condition. usually i find a filter is good for two or three normal oil changes of 3-5000 miles.