CD's has not been around long enough for us to have real experience on what kind of lifespan we should expect... A few observations have been made though: Use the gold plated ones, they appear to have a longer lifespan. The green ones appear to have the shortest. What happens when they fail is that the metal layer separates from the plastic, causing the laser beam to reflect back without having read the information. This can happen for a number of reasons. Bad manufacturing is one, of course, but the way they are stored matters as well. Plastic is not the tough, infinately durable material we like to think it is. It is very vulnurable to both light and moisture. Keep the CD's in a dry space and not in direct sunlight. When your PC says that the CD is unreadable, it only means that is can't read the directory. This is a very tiny bit of information compared to the entire CD. The actual data might be totally OK, but if the PC can't read the directory, it can't find the data. If this happens, you can usually recover almost everything using software that scans the entire CD for information. If it's valuable information, it's definately worth the expense.