unfortunately for me, i have to live in a very dusty environment. so i clean regularly to make sure that the case is dust free. regularly however can mean anything from once a day, to once every few weeks depending on the dust levels. but i try hard. as for computer maintenance? as far as defrags are concerned, i defrag everytime i uninstall/install something on my computer. no point in defragging if you haven't added or removed anything lately. it's hard to have file fragments with nothing happening. typically my computer runs fairly smoothly unless i'm running skype. for some reason skype takes up enormous amounts of RAM just to run smoothly. and it sucks up bandwidth worse than a vacuum. dead god.... every once in a while, i'll feel like my hard drives are too cluttered, or my My Documents folder has too much crap in it, so i'll go in and go on a binge deletion spree to get rid of anything that i never use anymore or don't need anymore. i also keep an eye on the temps inside my case. i live in a humid/hot area of the US so i have to keep everything in check. when i get my new computer, it will be no different.