A few things that I find don't get considered when contemplating backup procedures are:

1. How long should you keep backups for - is the content of your backup covered by privacy laws that require you to not have copies of it after a certain period of time? is there a point where the content of your back up is so old that it's the logical equivalent of not having made a back up in the first place?

2. How much does your backup process cost - if it costs more to back up a system than it would cost you if you lost it, then you've got the backup process wrong (interestingly this can be affected by economies of scale)

3. What do you need to restore a backup - does your system requires bespoke hardware that might have been lost in whatever disaster you're trying to recover from?