One of the most eye-opening concepts MMM ever brought up is the idea of using craigslist as a storage unit. If you don't need something, "store" it in craigslist. Then when you need it, just go bring it out of storage.
The same is true for libraries. I love books, and have had a huge personal library for many years. But now my library is hundreds of times bigger, with a full-time paid staff!