I've got a set of Coker's that are at least 20 years old. Now mind you, these tires don't have a lot of miles on them but show very little wear or rot. They spent about 12 years in the attic - so guess that helps.
It appears that I too will be stimulating the economy soon also, as although those tires look pretty good I just don't feel right riding on rubber that old. More than likely, if I wait too long I won't be able to find the dang things at the rate factories are closing, so better spend something before I can't get a new old tire.
Don