I'm sure the majority will say replace them, but I'd probably run them unless I was going to run it for hours at 100mph across the southwest desert like Cowpuc!
I just replaced the worn out rear tire on my Kawasaki that was 15 years old. It was 5 yrs old when I bought it from The Motorcycle Superstore. The front I'm running some more because it isn't worn out yet and it is 11 yrs old. The front tire on my RSV recently acquired is 12 years old, 23k miles on it with some tread left, and I am replacing it with new along with the punctured 5 yr old rear tire. Don't do what I do! Ha!