Your hard drive will crash. Will your data be safe?
There are lots of tools to backup your data, but the most important tool is you. You have to decide to make backup a part of your routine. And you have to know what files are important to backup. Do you know where your pictures, music, financial and other valuable data are stored? Well if you don't know, how can you do a backup?
The first step in doing a backup is organizing your data. If you store important stuff all over, then you may never know if it is all getting backed up. It's best to keep your stuff in a well defined location. Add a second drive to your machine and store all your important stuff there. Then it's easy to do a backup.
Do you backup your email files? Do you know where they are stored? They are stored separately from your other data. It's not hard to back them up, but it is a different process. Do you backup up your browser settings? Maybe you should consider that.