The machine would not reboot, nor could I access any data on the drive. The next morning was a flurry of intense activity. I notified clients of a brief delay. I ended up running out and buying a new disk, installing it, reinstalling all my software and restoring most of my precious work from that tape. Eventually, the manufacturer replaced the dead disk.
Disasters can and do strike ordinary people doing ordinary things on a computer.
Your responsibility is to be prepared. In my case, the hard drive crash was softened from a disaster to an inconvenience, all because I had that backup tape. Fortunately, Linux comes complete with a set of utilities that make backups safe, easy and reliable. Plus, several commercial and free software options exist to automate and simplify the backup process. Ideally, backups should be performed daily.