I agree, but my cellar is really tiny. So I keep stuff for a while and once I stuff more into it, I have to get rid of some older stuff I thought I need to keep. At least this leaves some time to decide what to get rid off. And actually, if you have something in your cellar or attic and haven't touched it for years....
Ebooks are a lot different here. With hdd storage being so cheap, I sometimes lose track of what I have and what not. You may know such thoughts like "Uh, I didn't know I ever bought that music. What did I think?"