Here's a back-up story, provided by our local computer shop.
One of the nearby businesses called my friend at the shop to say they'd had a drive failure that needed sorting out. The techie went out and was assured that it should be easy to fix as they had religiously backed up every night (for over two years) and kept the disks in their safe.
However, when he looked at the disks the file was surprisingly small. Tiny in fact. So he asked if they could give him a demo on their other computer, and show him exactly what they did. Sure enough, they were rigorously doing a backup at the end of every single day...... of all the icons on the desktop. Nothing else. :
It cost them more than they had bargained for to retrieve the data, but if you want it back badly enough you can usually get most if not all of it back.