If something happens to your computer and you don't have a backup, Very Bad Things will happen. Puppies will die! (Okay, maybe not, but you will curl up in a corner and cry for a very long time. Result is the same.)
Her Grace has lost work in the past due to lack of backups. She's learned her lesson. She hopes you do as well, preferably the easy way. One good place to keep a backup is in a fireproof safe on a well-guarded military base. Should anything happen to that, there are worse things to worry about other than the state of your backup.