First DIY writeup.
My 09 has 30k on its original cabin air filter. I took it out and it looked nasty. Pine needles fell out, etc. See the pic...
So I went to Autozone to buy a replacement and hoped I could get something carbon or charcoal to help take care of odors. They only had a replacement STP filter for $13.
I went to Home Depot and purchased the home filter that's adjustable for $10. It will be able to make many more filters in the future.
After installation, the flow may be decreased a bit, but I don't have the climate control on "high" that often. But the air smells great!
Total tools needed: scissors
Total cost: $10
First step is removing old filter. Remove glovebox by opening it, removing the black "shock" on the right from the bottom tab, then lowering and pulling out.
You will see two tabs holding the door to the filter. Press down on each of the tabs and the door will swing open. Filter slides out. (You can see this in the last pic).
As far as creating the replacement filter, the pics should suffice...