Back in January, we had a break-in at St Columba's. Some ill-mannered individual smashed their way in and trashed quite a lot of cupboard doors. Ultimately, the only item they took was a four-year-old laptop which was getting a bit creaky anyway. The laptop itself was probably worth a couple of hundred pounds tops, but as is the way with small organizations, it contained a bunch of irreplaceable data about our hirings and general admin.
As I recounted this story to a few geeky friends in the pub, they all sucked air through their teeth and began to commiserate with me about what a pain it must have been to try and replace all that un-backed-up data.
"But no!", I was able interrupt them (with just a trace of smugness). Despite this laptop being a standalone machine whose regular users are completely un-technical, there was a backup system in place. It involved a Python script which used rdiff-backup to shove the laptop's hard drive the wrong way up the office ADSL line and onto one of my servers. It shuts down the laptop when it's done (many hours after you start running it), so all I had to train my users to do was "click this icon before you go home on Friday". So we lost a few days' worth of data, but it could have been a lot worse. And the solution took about an hour for me to put together and cost nothing.