With iCloud coming...I'm not really terrified of losing my purchased media from iTunes. However I still do back up all my CD rips at least once a month. It would just suck having to re-rip all my 500 some CD's I have in my library. And, scanning a few 120 album covers again because I didn't like iTunes versions. So how often do you back up to a local external hard drive, or if at all?