I can not stress how important it is to make regular backups of the important data on your computer. I backup certain files almost daily and have been doing this for years. I was lucky in that I started this practice a couple of months before a hard drive completely died.
I didn’t have any hardware failures recently but was having software problems (Windows). Earlier this week I got fed up and decided to reinstall Windows and restore from a disk image. And I didn’t have to really worry too much because I knew my external drive had all of the data that I wanted to keep – actually it probably has more than I need and I should clean it up.