When applied in the proper amount, the product should stay fluid for the life of the tire. If it is constantly exposed to fresh air, it could dry out and need to be replaced. Repeated punctures, causing some loss of fluid each time, could eventually deplete the fluid to the point that repeated airing of the tire could cause some setting up of the fluid. This is caused when a regularly applied amount of fresh air replaces the vapor atmosphere as the fluid level in the tire drops.