HI, been there so many time I’ve got a closet full of T-Shirts…
@pspeed is right about using a simple SVN (though I will admit I did that and found my old ways creeping back).
So as the adage says “Back up as often as you can afford to lose”.
And on a brighter note I personally have found that EVERY time I had to rewrite what I lost it came out BETTER!!!
Sidenote: Data recovery from windows is much easier than on *nix, for the FAT keeps the lard.