One of the first things I was taught when I got into computers years and years ago (how long ago was it? To Bill Gates, Windows was something you looked through to see outside) was to make backup copies, because if you don't, you'll lose your stuff. But as the years go by you start to disregard warnings and guidelines, and sooner or later you pay for it the hard way. There have been times that I didn't backup and lost everything that I wrote. There have been a few posts on this blog that I've had to write again from scratch because of that.
And there are other things where having a backup copy will come in handy. You can make backup copies of your disc media with the help of dvd-ranger. The copyright laws allow owners of DVDs to make a backup copy for your own personal use. And there are additional features such as upcoverting your backup copy DVDs to blu ray, which will come in handy if you're planning to upgrade your personal media from DVDs to blu ray, and can save you money if you're not planning to rebuy your DVDs as blu rays. Just make sure you don't get rid of your DVD copy so you can still own your backup copy. Not only that, but you don't have to worry about something happening to your discs because you have a backup copy.