question about audio tapes, if anyone knows

Do unopened, unused audio tapes go bad?

I picked up a box from my storage unit today and in with the cassettes, found 5 unopened tapes (3 Maxell, 2 Sony). I know they've been in the storage unit since July 2006 - would they still be good?

And if they are, does anyone want them? :)

Actually, let me add a question: same thing, but video tapes? I'm fairly sure I have some unused video tapes too.