Recently I came across a handy piece of free software called SyncBack. It allows you to setup a schedule for syncing folders on an external hard drive with folders on your computer, making it really convenient to back up important files on your computer. For example, I have it set up to back up all my work files every night at midnight, it backs up my photos every Monday night, and it backs up my music every Tuesday.
Anyway, I found it very useful and easy to use so I thought I would share my experience with the world. If you want to check it out, here is where you can download it.