Do a trial run of a restore. I've seen too many backups fail/be incomplete to trust that backup works without validation; test that you can get back what you need to.
The most comically tragic "failure to effectively test restore" story I'm aware of is from one of our customers, who previously had their own home grown backup system with encrypted archive shipping offsite, monthly test restores, and so on.
It was only after a total failure that they realized the gpg keys to decrypt the backup were only contained _in_ the backup. Their test restores before were happily using keys from the user's home directory.
This is one of the many reasons it makes sense to have a company that specializes in backups help you with backups. :)
