MOST tire manufacturers recommend in writing on their websites, inspecting them annually at 5 years and as long as the inspections show a good tire, to continue use to 10 years, then replace them. Of course all the "tire engineers and manufacturing experts" on here will tell you that anything over 5 years is just asking for trouble and that the manufacturers do not know what they are talking about. For what it is worth, we have a 56 classic auto and I still have the "original" tires which are still holding air and the weight of the vehicle. Amazing that with all the technical progress over the past 58 years, that tires are junk today, according to the experts here.