I replaced mine religiously every 20K miles (hay fever is bad in the Willamette Valley - and it really helps). I got a bit lazy as my car piled on the mileage(107K now) and last year I had a problem where my HVAC fan would ROAR when on high speed. Couldn't figure it out! Took it in to the Ford Dealer and they immediately said the cabin air filter needed to be replaced. They were right. INCREDIBLY dirty. Caused the HVAC blower to cavitate. Roars like an F-4 Phantom at full afterburner smile

Just an FYI everyone. When the filter gets badly clogged, you WILL KNOW!

Regards,
Jab


Learning about cars from my Contour 95 LX - PLEASE do NOT BREATHE on my wiring harness! I can't afford a new one!