Regularly testing the restore process can be a bit inconvenient and time consuming, but does have its uses.
I heard a story from a consultant about a bank that had trouble with a restore. It was a mainframe shop, and they called in the consultant after the in-house people could not get a particular file to restore that was desperately needed.
The bank showed the consultant the script, on one of those old 24x80 monitors. Indeed the file name was in the backup script, somwhere on page 3, so it should be on the tape and it should be possible to restore it.
The consultant had another look. At the foot of page 1 of the list of files, there was a /*. Mainframe folk will know this as an end-of-file mark. All of the files listed after this had the status of comments, The consultant then had to explain to the bank exactly what 'non-recoverable' meant. The good news was she still got paid.