Generally 5-6 years is the recommendation. Goodyear with their travel trailer tires for sure recommends 5 years. Mine blew the sides out of 2 of the OEM Generals at 5 years with the camper sitting in its' winter parking area. The Australian made replacement Goodyears are looking fine after 2 years and a fair number of miles. As a note on Goodyear Wranglers for p/u trucks - while they seem to wear like iron, they heat harden after 2-3 years of operation and become very treacherous to the point of having very poor wet weather traction - from personal experience on 3 different trucks (plus Tire Rack reviews say much the same).