I use this for backing up:
Code:
robocopy D:\ X:\ /e /mir /tee /mt:4 /XD "D:\$RECYCLE.BIN" "D:\System Volume Information"
(In Linux, when I use it, I use rsync in the same way.)
It basically backs up my D: drive, which contains all my data, to an external drive at letter X:. I also have a second drive configured at letter Y:, which is at my mom's house. I swap the drives every two weeks or so.
So, I can at most lose two weeks of data, and that will only happens if my computer and the backup drive fail all at once. For that to happen, the computer probably has to be struck by lightning while it's creating a backup, or the house must burn down. If the latter happens, I don't really care about two weeks of (possibly changed) data.