Back-ups
Daily; back-up to 2nd hard drive. Unless have made major changes to data or O/S. Then.....
Most used files are synched to three different systems with flash drive. (Mostly my writing.) While Wondoze sucks in a lot of ways, Briefcase was, and is a good idea.
Weekly; Changed files to CD. 3 copies, one in rack by computer. One in my CD case. Last one is in my desk at work.
Periodically: complete drive image to second drive. Replacing last one. About 6 months to yearly intervals.
I've lost far too much in the past. recreating forty pages of writing isn't as easy as you might think. So, I am slightly anal-retentive about it.