I'm much less systematic but do keep drives in different places which protects me from theft or disaster like fire. I occassionally back up what I think I have been working on for a long time to an archive hard disk (meaning, if I think I have a day or more work on something, it gets backed up like that). In between backups, I tend to put what I am working on on the hard drive that I transport (that is the one I dropped), and some of this gets copied onto other computers at the University here (Missouri).
Chris