for the guy 'bout damaged disc, backup isn't a solution. Take care of your disc and nothing will happen. I still have good old vinyl disc scratchless and none of my compact disk are damaged.
How about those good old tape? Playing them too much worned and damaged them and nobody complained.
For game, it's the same thing. You damaged the disc (let's say broke in half), get a new/used copie. Normally by the time you want need it, price will have gone down (which doesn't happen fast on movie and music). If it's only scratched, get to your local gamestore/video store and ask for a buffing. Here it cost 'bout 5$ and the disc get brand new.
Also, I know some cie in the past used to replace the disc if you send yours. A friend of mine broke some, call the tech support and replaced the damaged disc for a fee. All he had to do is send the disc with the money and some week after, he got a new disc.
Like someone else said, you don't go saying you "own" your car or your t-shirt once you broke it and ask for a free replacement, why would you do the same for broken disc? They even last longer then any of those thing. A disc can virtually last forever if you take care of it.