My 2005 Suzuki(GM/Daewoo) Forenza(Nubira) has a cabin air filter. It does seem to keep the interior cleaner. The problem is that the dealer wants $25 for the filter and it needs to be changed every few thousand miles. I did find a WIX substitute and ordered a few from Rock Auto. They still cost over $10 with shipping. I let the last one go for about 10,000 miles and it was pretty plugged. I put a new filter in last night and the difference in air flow was dramatic. If I had let it go much longer I might have fried the blower motor. After the ones I have are used up, I'm not sure what to do. I don't see any big benefit from having one, other than to keep leaves and stuff from plugging the A/C evaporator. I can dust my dashboard once in a while. These are my three options: 1) Keep buying and replacing them every 5,000 miles before they plug. 2) Retrofit one with a piece of window screen to keep the big stuff out and clean it once a year. 3) Just leave it out. Suggestions?