I'm not too worried. The technology for reading digital material is so widespread now that a planetary collapse would be necessary to wipe all the reading tech off the map.

The materials in DVDs/CDs have a limited lifetime. I think it's in the range of 50 years, but since the material hasn't been around that long, we have no real data. Certainly books easily last much longer under proper storage, and if made from proper materials.

But the way I see it is that information storage technology changes so rapidly that no digital information will ever get a chance to wear out before it's moved to something else and better (we certainly have an easier time copying a book than medieval monks did).

Information can be duplicated so easily that it would be almost impossible today to pull a "Fahrenheit 451" on literature. In Bradbury's book, several thousand people each preserved a book by carrying it memorized in their heads. I could do that now with something that I could hide in my mouth. In "When Worlds Collide" (the book, not the movie) they insulated the spaceship with thousands of books, attempting to save what they could of human culture. Imagine how much easier that would be now. I can buy a thumb-sized flash drive at Walgreen's for twenty bucks that has thirty times the storage space as the $1,500 Core drive I got for my second PC.

Current flash memory is limited by a certain number of read-write cycles, but the best types are good for about a million cycles. I'm not sure a book could stand that much reading, either.

I think information technology is on the verge of immortality. In the future, I see no theoretical reason solid state devices should ever wear out, and by sheer dispersion and duplication, something should always survive.

But I'm still old-school enough that a book with pages is still more comfortable for me to read than anything else, and there's nothing that smells as good as an old bookstore or library.