Is redundancy in backup really important?

Episode 1409 (1:32:20)

Phil from Aurora, CO

Phil wants to know if redundancy in backup is really that important. Leo says that it's vital, and not only that, but he'll need off site backup as well. Is Carbonite necessary? Leo says it's valuable, but he could also just leave a second hard drive at work or at his mother's house and just swap them from time to time.

(Disclaimer: Carbonite is a sponsor)