When to get new tires

The National Highway Transportation Safety Administration primer on tires states that rubber degradation accelerates after 5 years and therefore tires should be inspected more frequently and diligently once they reach that age. All tires on a TT, regardless of age, should be inspected before each trip and have the pressure checked. There is no absolute rule on when to replace but the clock is ticking much quicker after 5 years. Current set made 6+ years but will be replaced on Saturday morning after I discovered an issue with one.