Ah, memories...
About a quarter of a century ago, I installed a painfully expensive tape backup system for a customer and left instructions on best practices, including regular manual trial restorations.
About a year down the track, disaster struck - as luck would have it, when I was interstate with no easy/quick way to get back.
I had a local agent pop out with a replacement drive, but he said there were no valid backups to be found. Quizzing the customer yielded something to the effect of "we started getting tape errors so we removed the tape and the errors stopped."
They hadn't performed a proper backup in months, had only done one trial restore about a week after I set the backup up, and didn't even think to get a replacement tape or simply roll onto the next day's tape - nor even to call me for advice.
No skin off my nose as they were only a casual customer, but it really makes you wonder just which cereal packet some people got their brains from.