Originally Posted by Dak Drexl
If you always lose your discs, you can burn them to your HD ahead of time. Since you bought them, this is not illegal and you are just backing them up.
Most legal text I've seen on video games says that making copies of the disc content is illegal, regardless of whether for private or public use. Sure it isn't as serious an offence as redistribution, but yeah, it's not legal, neither is downloading roms to keep for 24 hours. The legal text on Total War: Shogun 2 even warns against unauthorised borrowing/lending, so your friends had better buy their own damn game.