Just had my 15K Mile maintenance done and they told me that the two filters were due for replacement according to the schedule. There is the engine air filter and the cabin air filter (dust and pollen in the passenger cabin). I chose not to have them replaced since I've been watching the engine air filter and it's clean and fine. But not sure how to get at the cabin filter but plan on finding out and will post when I do. This is an area best left to the owner in my opinion but then again I’m a do-it-yourselver that keeps in eye on things like this.