Making Christmas decorations is easier when you never throw anything away! Here we decorated our doorway with old greeting cards. They don't even have to be Christmas cards, but we picked more colorful ones. The difficult part was getting it to stay up with paper-clips and Scotch tape.
Later my roommate walked in and asked, "Do you know what I can do with my old socks?" And I pulled out a book of instructions for how to make stuffed animals out of old socks and gloves.
It's not hard using old things...but it is hard to keep from acquiring new ones!