There might come a time in my life where I'm into KonMari or one of the other decluttering trends sweeping the nation. Until then, here's a simpler approach. Pretend it's a flowchart, OK?
Does it have dust on it? If so, you haven't been using it much. Dust it.
Do you want to dust it again in two weeks? If yes, put it back where it was.
If no, do you actually need to keep it?
If yes, find a different way to store it.
If no, get rid of it. (If possible, donate/sell, but trash needs the trash can.)