Most people know they should be backing up their computer. Or at least I think most people do. However in my experience the average home computer user rarely backups up his or her data. Occasionally a USB thumbdrive might be used for some documents or an external hard drive for photos, but chances are if the internal hard drive died, which happens more than people think, the majority of the important data like pictures, music, emails, and documents would be lost. There are hard drive recovery services but they are very expensive costing anywhere from hundreds to thousands of dollars to recovery the data. And that is only an option if you still have the physical drive. A stolen computer or lost laptops that isn't backed up will probably not be coming back.
The good news is there are a lot of available options to backup your computer. Most operating systems come with backup features built-in and most backup software is easy to set up and automate so it runs on a schedule automatically with little or no input from the user.