Four or five? I just keep two back-ups. People tell me that's excessive.Every evening, my laptop backs up to my home desktop at 10pm, and every weekday afternoon at 1pm, my laptop backs up to my office desktop (both chosen to maximize the chance that the backup will be over a LAN). In the evenings at midnight, my home desktop copies its backup to one or two of its other drives.
Wow . I never back up my files, except really important files and projects.