I have a 44 Laser Z with Kawasaki engine. What is the life expectancy on these paper air filters? I blow it out every weekend or about every 20 yards or so. This is the first engine I ever owned that did not have a foam pre-cleaner on it. Personally I would like to have a foam cleaner with the paper filter but it seems to me its a way for exmark to make more money off of these filters.