Well, if my hard disk conks out, I simply have to buy a new one and restore all project data from my backup hard disk. I think, a RAID system only has to guarantee an absoluteley uninterrupted service - normally required at web/file servers. But this doesn't supersede or even matches my backup necessities. So, I personally never used a RAID system and actually never missed it, too. ... Hope, I'm not on the wrong track! :-D