The warranty period for new tires is preferably within two years. If this period has passed, it is not recommended to purchase and use tires that have never been used before. Off-road tires, especially AT tires, adopt a deep groove design. Even if they have been driving for several years, they may not have had a smooth journey. But don't think that just because the tire groove is still deep, there's no need to change the tire. Since the tires have been in use for more than two or three years, considering the problems of oxidation and wear, even if the tread grooves are still deep, it is necessary to pay attention not to drive at high speed. If economic conditions permit, it should be replaced.