CD collections

Alright, since I had all of one post today - I'm going to try and incite some conversation here re: CD collections. I personally have loads of CD's in my collection, and while a majority of them are bands I like, not of all them are going to ride the wave of longevity and be with me till the end of days. So, how do you go about deciding what needs to go and what might possibly perk your interest someday regardless of how you feel about it now? OR what are some CD's in your collection that you don't know why you have them now or why you haven't gotten rid of them yet. I.E. Mad Season - Above.. that one needs to go and will find it's way to the used bin sometime this weekend.