At what age should tyres be replaced? Tyres will normally wear out before they become unserviceable due to ageing. Tyres degrade naturally through exposure to heat, sunlight (Ultraviolet/UV) and rain. The amount of damage depends on the exposure and the severity of the weather. Damage through ageing is more common with caravans, trailers and other vehicles only used occasionally. There are no hard and fast rules on age. Check for signs of cracking on the sidewalls of tyres four or five years old if your car is parked outside and get them replaced if cracking is severe. Any tyre specialist will be able to give you advice if you're not sure.