When your backup fails go to your secondary backup. When your secondary backup fails, cry. It is rare but it happens. Just when you think you have everything covered shit happens. Some people can go years without backing up and have no problems. While you on the other hand have gone through 5 drives in 5 years. Bad luck? Maybe. Bad habits? Definitely. Time for online storage? Start looking. Because when your multiple backups start failing you've got big problems.