as far as i understand what Brahn is trying to ask here is how does the CD-rom or dvd roms gets damaged. Most probably hes talking about the lens in the cd-r or dvd-r. Well brahm if this what your trying to ask here is then maybe i can throw a bit of info but im certainly not sure whether its correct or not, im just telling u out of my experience with the darn things.
1. Pirated CDs---- the quality of the cd's may not be so great which cause the lens to read more which can cause the rapid deteriating of the cd-r lens life.
2. Sometimes a lot of dust gets stuck on the lens of the cd-r or dvd-r which in turn when runned can cause a lot of scratching on ure lens and ure cd-s.
3.Your using the darn as a cup holder.
.....
Although a cheaper thing to do is that whenever ure lens gets burned out simply replace it rather than buying a new one. I always do this myslef and it saves me a bundle on new Cd-roms.
Hope i helped u out here...