A team notices that database backups are completing successfully every night, but a recent restore drill revealed the backups are unusable due to a schema-version mismatch with the current restore tooling.

This demonstrates exactly why periodic restore drills matter — a backup existing and a backup being restorable are different facts. The fix isn't just regenerating a compatible backup; it's establishing a recurring (e.g., quarterly) automated or semi-automated restore-drill process so a similar drift is caught proactively rather than only during an actual disaster, when it's too late to fix calmly.