I just don't see the point in the extra cost of RAID1. Sure, if you have an unlimited budget then why not, in fact why not run RAID1 on 4 disks? It guards against a single problem, not accidental deletion, not filesystem corruption, not malware, not power disturbances, not physical damage, not anything but a HDD failing by itself. Yes, it can happen but amongst all the other (more likely) scenarios, it's money wasted IMO. RAID was designed a fair while ago so you could combine some cheaper disks instead of using a much more expensive reliable disk, today's cheap HDDs are far more reliable and in a home environment it's generally used either for performance or through the assumption it's a substitute for backup. I mean RAID does have its uses but it's not what a lot of people think it is.