If your Mac isn't being backed up (iCloud is not a backup!), then you should set one up ASAP. Why risk losing your documents, photos, music, or other files? How long would it take to set up a computer all over again? People tell us they don't have a backup because they aren't sure how to do it. Here's how:
1. Buy an external hard drive. Pretty much any drive will do, as long as it says "USB 3.0" on it somewhere. You can buy them at Amazon, Target, Best Buy, or even Sam's Club (although they might want to sell you a 12 pack!).
2. Plug it into your Mac. If you don't already have a backup configured, the Mac will ask you if you want to use the new drive for a backup. Say yes, and you're done.
It's that easy! From then on, as long as that drive is connected to your Mac it'll make a copy of your files onto it. If you have a laptop, just be sure to plug in the drive periodically and leave the lid open so the computer can back up to it.