Buy a new hard drive every year, make it your primary drive. The previous one becomes your backup.

Or just keep it attached to your system, so spyware, adware, and the NSA will make free backups for you!

This has been my system for a while now. The funny side is that, I have yet to have a drive failure so the amount of local backups is getting silly.

The other thing I did was I ended up collecting HDD's out of old DVR's people were throwing out. Those drives are used for cold storage but not for anything important because they already have tens of thousands of hours on them and in not the best temperature conditions. Again, non have failed yet.

Funnily enough, the only HDD I have failing is a 2.1GB Quantum Fireball from 1997 in my Pentium 1! Really should swap that for an SD card via IDE.