If you are using Valvoline VR1, this is a healthy 1400 ppm of zinc. The foam filter is intended to keep larger debris away from the filter media which can extend the life. A lot of people lift the cover, view the foam and think it looks good, but never check the paper media below it. My recommendation, since you don't need a tool to remove the filter, is to remove it regularly and pull back the foam. Also look inside. It literally takes 1-2 minutes at best. You should see zero evidence of dust/dirt on the inside. If so, change the filter. Looks like you have a good system. Keep it up.txmowman---I am not in extreme conditions, except living in south Louisiana where summertime temps are 95+ degrees with humidity at that level or higher. The occasional fire ant mound is really the only dust that gets kicked up, or if the wind is blowing stuff toward the engine. After each weekly cutting, I do lift the air cleaner cover and blow out any debris with the leaf blower---no compressed air. I do also have a foam pre-filter. I just started using Valvoline synthetic racing oil because of the higher zinc content and claimed anti-wear properties. Also, I plan on removing the blower housing to inspect for and clean any foreign debris. Thanks for your advice!!