...I have used 8 yr old SignGold for my own stuff and it was still OK. Very little tunneling and still sticky. But I don't think I'd use it for a client's job after about 4 years just to CMA, but then again they claim it lasts what...10 years outside? As long as it's been stored in its original box rolled on its big tube I think I'd try it out. Like I said, for your own use tho. I'd do a job on glass because if it did fail it's easier to scrape off.