I was thinking about hording lately, which seems to be a particular problem to us creative types. It's something I continue to struggle with and something I see friends and family struggling with too. We see something and think "Ooo, that would be perfect for X project some day in the future!" or "I don't know what I'd use this for but it's so cool I have to keep it!" But really, what I'm often holding onto is not the thing itself but the DREAM of the thing. The "one day I'll do this" dream. As I get older I realize I don't really have the time, or even the inclination, to follow all those dreams and so paring down becomes easier.
Although that doesn't happen for everyone. My dad recently bought a pair of bowling shoes, despite the fact that he hadn't been bowling for about 5 years, has Parkinson's disease and doesn't own a car! But the dream of one day bowling was so compelling that he bought the shoes. (I decided I had to do something about this particular dream and took him and the boys bowling this weekend, but I'm hoping he can put aside the dream of covering every available surface with old copies of Scientific American... ) :P
I've found once I got over the initial shock of "de-accessioning" as I call it (all those years working in a museum made their mark) I find I'm generally happier. I can concentrate more on what I really love, I find things more easily and can clarify my project goals when I am not so distracted by all this stuff. Plus there's more room to work! That's not to say I don't fall into the collecting/hording hole still, but it's less often and I'm more aware of it than I used to be. So when tempted I try to ask myself if I really want to be a collector or a costumer, and that helps get me back to what I truly love, which is creating.