I don't clean mine out enough. I've never even opened the thing up! I have a laptop now and all I've ever used is an air can duster to blow out the vents. Before, I had a tower computer, and that thing got pretty nasty inside. I did smoke quite a bit while using it but can't confirm that smoking was causing the nastiness. I used that old computer for about 8 years before I junked it. I still somewhat miss it for some odd reason.