Gil signed up with Carbonite and after his computer crashed he tried to restore his data but they didn't have any data for him since 2013. Leo says that even when using a backup, it's always a good idea to check and see it's working continually. Don't just trust that any software is automatically doing what it's supposed to all the time. This is also a good reason to have a 3-2-1 backup strategy. Three different copies, on two different media formats, with one off site. That way if something goes awry, he'd have a back up of the backup.
(Disclaimer: Carbonite is a sponsor)