I am a little concerned with the inside of my case and all the components. Is it common for like dust and crap to get inside of cases or can this be avoided? Reason I ask is because I noticed on some friends' computers there is alot of built up stuff on their fans and components. If this cant be avoided, is there a safe way to clean everything off? I'm not anal or anything I just want to take of my stuff and it took alot of time and effort to get my Comp the way it is. Thanks for any help/suggestions!