Perhaps one of the most overlooked areas when it comes to backup processes in general that most organizations fail to execute in their backup plans is backup verification. Often, many administrators may simply assume backups to be good and the topic goes no further than that.
When I worked for a telco in the 80s they had a nightly script for two backups over three tapes. The script asked the operators first for tape 1 then tape 2. Started the second backup which asked for tape 1 again. This overwrote the first backup. Tape 3 was never used. I found that problem before they ever needed a restore.