My ET Street Radials are still good after 3 years, about 70 runs and 5000+ street miles on them. I know they are still good because I got my best 60 ft time (1.64) last time out. When not racing for an extended period I put my street tires on, lay the ETs on their side and drop the pressure to about 5 psi. Otherwise I leave them on the car and drive it often.