The more stuff you have, the less time you have for yourself and others. Stuff keeps you from thinking too much - you're too busy getting it, storing it and worrying about it. Clutter can be oppressive and depressing . If your possessions are in need of repair, that can add to your feelings of depression and failure. Stuff takes on value only when used.
Unused stuff is just junk or clutter.
How often you use it determines its value. Less use, less value. That's not to say that something has to have a strictly utilitarian value to be worth keeping. Some stuff is enjoyed by your eyes. It adds beauty to your life and therefore is being used.