My wife found a website by a woman who advocates a "27 fling boogie." Grab a trash bag and throw away 27 things, then stop. She also does it with things that should go to charity...
My thought is - if you haven't used it within a year, or if getting rid of it doesn't require hospitalization, then out it goes. I used to do a lot better with that, then my truck died. Now it either has to be small enough to put out with the regular trash or I have to borrow a truck (which I hate to do).
One of my favorite bumper stickers: Yes, this is my truck. No, I won't help you move.