I strongly recommend everyone backup their computer; portable hard drives are relatively cheap nowadays. I've been especially strong with my advice to laptop users. The nature of these portable drives, pushing the limits of technology and more recently the amount of heat these things produce tends to make them fail much more often than normal.
Unfortunately, I have been the victim of an incident lately where I grew lax in my backup habits and let things go far longer than I should have. It almost resulted in a critical data loss, but fortunately I realized the drive was failing and was able to get my critical data off before it was too late, but only just. I got 4GB out of 30GB of data off the drive before it croaked, and in a twist of pure luck my important documents were in folders that started with early letters in the alphabet in my home directory.
I had grown complacent and had neglected backing up my laptop since October. Having moved my most critical data, I was thinking, to my desktop, that's backed up so I don't need to backup my laptop as often. However my laptop has become far more critical to me than I realized and it had accumulated quite a bit of data that never made it to my desktop. As I become more mobile this trend is likely to do nothing but continue.
I was lucky, but as technology keeps pushing the envelope on these things they are going to continue to fail. Back up your data, get in the habit, and don't stop doing it; that drive
will fail, it's only a matter of time.