The best way to test your backup is to try restoring data from it. You don't need to do everything, but restore a few files a couple of times.
If your backups fail on any given scheduled time, make sure you take the time to figure out why sooner rather than later. Don't procrastinate!
Make you learn HOW to restore your data when you are not under pressure. That way if a catostrophic computer event happens, you are ready to do what needs to be done and get back up and running!