How do you clean a filter like the cabin air filter? I have not pulled mine to see what type of filter it is, but if it is the same as all the others in my dealer's service department, it is not a cleanable filter. That would be like cleaning a standard fiberglass home filter.

I personally think the cabin filter will get dirty FASTEr than the engine filter due to air flow. When you don't have recirculate on, all the air coming tru the a/c is going through that filter, and the a/c system can produce a larger volume of airflow than the engine. Also our engine is designed to run at the least RPM possible reducing the consumption of air, and even turns off thus reducing air consumption even more. All this translates into much more airfloow through the cabin filter than the engine filter.

Either way, I think once a year is MORE than enough. The dirtier a filter is the better it filters to a point. Once the filter gets so dirty that it can not efficiently pass air through it, it will start to have some of the dirt pass through it, so you should replace the filter just prior to that point for best economics. What that point is, I don't know.