A fair amount of the people I talk to about backup say they forget to do it, or they can’t figure out–or never get around to setting up–the built-in backup options. If that sounds like you, check out IdleBackup, a utility for backing up your computer when it is sitting idle.
I still recommend making a daily backup of your important files. The downside to IdleBackup is that it only makes a one-to-one copy of your files. If you deleted something yesterday, it will soon disappear from your backup, as well. But if you are not backing up regularly, IdleBackup sounds like a good first step.