Backups are a MUST. I cannot say that enough. If you wrote it, if you LOVE it, if you don’t want to recreate it all again because it got deleted, then BACKUP YOUR WORK.
Invest in an external harddrive. Use a file hosting site that you trust (and isn’t very expensive). Burn everything to a CD/DVD. Use flash drives — just make sure you don’t misplace them or leave them some place.
Whatever your poison, make sure you do it and do it OFTEN. Programs and computers have a bad habit of eating work when you least expect it. There’s nothing more devastating or depressing than spending hours writing thousands of words only to have the computer delete it like it never happened.