Many eons ago when I worked at a large company we used Alpha4 (Dbase clone). That version of Alpha4 was not multi-user friendly. Regardless, I put a database that 3-5 users would be accessing on a network drive (other option was to use my PC and my getting up any time another user needed to use the database... and that was NOT going to happen). If two users accessed the same data, the database became corrupted. Because of this, I set up batch files to back up the database that I ran before lunch and just before I left work each day. If I wasn't in the office another user ran the batch files.
That worked great as long as I was in charge of that project. When I transferred to another department I showed my replacement the batch files and explained how vital it was to run the backups twice each day. Fast forward 18 months later and that replacement's replacement calls me about not being able to access the database. I went back to the old department and found that two users had indeed tried to update the same record at the same time, so the database file was corrupted. I checked the backups, and they were there.... and they were almost 7 months old. Coincidentally, the new guy had been there for 7 months. Doh!
He was fortunate, though, as the network adminstrators were able to pull the database files from the prior Friday's backups (the restore worked). Also, the new version of Alpha4 that had recently been released was multi-user, so he was able to convince his boss to upgrade.