Since this thread was begun, I have added a new player to my computer backup arsenal. I bought a Raspberry Pi3 (an inexpensive single board computer) for $35, plus a power supply and case for it - total cash for all that together was about $50. [edit] $50 for the Pi itself, and the power supply, and the case [/edit] Then I bought an external USB hard drive. 4Tb, and hooked that up to the Pi. I installed UrBackup software (free) onto the Pi. Then I installed UrBackup clients on all our computers (some Linux, some Windows). Now, every night, each computer is backed up to that 4Tb external drive. I can restore a copy of any file, chosen from all the different versions that were saved each day. I also have it doing image backups of each Windows computer in case I need to do a bare-metal restore. (The UrBackup software does not yet support image backups for Linux, so I just use file backups there.)

You all might want to check out this UrBackup software if you're needing something like this. You can even do remote computers - the don't have to be on your LAN.