Just went to a side job a buddy of mine gave me. He said it wasn't cooling and wasn't getting any air coming out of the vents. Of course the first thing I think of is to check the filter and didn't find one. Went to the air handler and I'm not exaggerating one bit, I found 3/4" of dirt, grime, hair and everything else on it. Not only did I find this but he just got done painting his house (with a sprayer) and the top layer was nothing but semi gloss white paint. A gallon and a half of cleaner, close to 500 gallons of water and 3 hours later it finally came clean. It ended up costing him a good chunk of change and I just could not help but rub it into his face that what cost him $XXX.XX could have been prevented by spending $6-$10 in filters these past 6 months. Gotta love the idiots!!