I exchange my K & N filters every 3 Months, or 5000 klms. That way there is always a clean air filter doing it's job. I do it when I change the
oil. Surely it's no bother when you change the
oil and
oil filter to add one more little task. It's like checking front wheel bearings. Only another five minutes a wheel. Besides, repacking the front wheel bearsings is only a few minutes to check for safety anyway. You want to run harrd? Just do it!