Backup software reports success when it finished writing. That is not the same as being able to get your company back, which is what you actually bought.
A restore test in one afternoon
- Pick the system that would hurt most on a Monday morning.
- Restore it somewhere isolated, from the backup you would really use — not the one the engineer prepared this morning.
- Time it. Write down what was missing, what needed a password nobody had, and what surprised you.
- Repeat with a date in the calendar, at least twice a year.
The result is a number you can tell your board: how long it takes to come back, tested on a real date. Almost everything else about backups is bookkeeping.