While 76 percent of survey respondents haven't lost data in the past six months, 24 percent have. Reasons for data loss include system crash (11 percent); accidental deleting (9 percent); virus (9 percent); lack of organization (3 percent); and other (2 percent).As someone who's been recently burned by two of these disasters - system crash and accidental deleting - I can tell you it's a real pain when it happens. Of course, I actually thought I had backed up more than I had, which only compounds the frustration. So, now I'm preaching back-up to anyone who'll listen.
And, don't just back up the "vital" files. I didn't lose too much stuff that I couldn't afford to lose, but I lost things I didn't value properly, such as photographs, etc. Those things are important too. Thankfully, because the pc was nearly brand new I only lost a few pictures and a couple of other files.
If I can make a recommendation, get Syncback. It's simply an amazing program and it's free.