Despite knowing better, most people don’t do backups of their personal digital data. If you do backups, good for you. If not, read this article by Mat Honan describing how he lost much of his digital life, then start doing backups:
Had I been regularly backing up the data on my MacBook, I wouldn’t have had to worry about losing more than a year’s worth of photos, covering the entire lifespan of my daughter, or documents and e-mails that I had stored in no other location.
Setting up a backup procedure is a one-time process that costs you a few hours and roughly 100 €. At the very least, have a hard drive that you copy all the data that are on your laptop / PC a few times a week – the copying can be done by specialized software and will take less time than you spend at dinner. Don’t use this drive for anything else and disconnect it if it’s not in use.