If you just blow the dust off... it just goes into tiny particles that still will accumulate through gravity settling overtime to become an annoying build up once again. - So when you do air clean your case... do it outside (Or in a well ventillated room) where the dust will be carried away. Turning the pc on its side with the heatsink hanging down vertically (need to have it on some chairs) and then use the compressed air. - This way all of that unsettled dust falls to the ground instead of backinto your pc case. - Air filters are ok... but they reduce airflow a bit. It really helps to have a clean roon too. So DO SOME HOUSEWORK! - yer right ;-)