A backup isn't a backup until you have successfully restored from it. Until then, it is just a very expensive file upload called 'Schrödinger's Data'.
@Natasha_Jay I discovered that last year. Luckily not a horrible disaster. I now have a NAS with a redundant raid array, multiple backups, all kinds of testing via zfs. I'm doing all I can do.
@Natasha_Jay Eggsackly. See also: Disaster Recovery.

@Natasha_Jay just last week I plugged in my old backup solution, a singular external hard drive, and found out that it died overnight.

It's like your mechanic that drives a beater car. IT pros do not always follow their own advice 😅

@Natasha_Jay So true. Unfortunately, so many people and places do not have the equipment or resources to do the testing. Testing your backups were part of a federally mandated requirement in the industry I worked in, but the system owners were so overworked and literally didn’t have hardware to test on. Not to mention it’s one thing if a drive dies or gets infected, but if the motherboard goes away, getting a backup installed and running on different hardware can be quite the challenge