Assuming it isn't scratched or otherwised damaged, can a CD or DVD
ever wear out through normal use?

Yes, there's something called "cd rot" which is starting to be noticed
especially on CDs which are older, and the first to be sold. I've
found a couple articles on cd rot, some of which are very recent.

http://www.cnn.com/2004/TECH/ptech/05/06/disc.rot.ap/

http://www.rdrop.com/~half/General/CDRot/CDRot.html

http://www.sundayherald.com/41888

So if you have any critical data, be sure to back them up every 5-10 years.

skermit-ga

I wouldn't have thought so.

Omigod ... Let's get back to tablets of stone ... And quick!

I don't think my computer has a Stone Tablet drive.  And is it
available in both ST-R and ST-RW?

From what I've heard, "CD rot" is often associtated with flexing the
CD, rather that just using it in a drive.  Flexing makes the metal
layer separate from the plastic, and bad things happen from there.

CDs haven't really been around long enough to tell how they last over
time.  I have some CD-Rs that are nearly 10 years old that still seem
to work fine (stored in the dark, not used much).

yes but i think a more better question would be does the laser
eventually wear out the data on the disk?