Hello Aidan, I thought that would spark a debate. The rears were 6 years old, the fronts were older (9 or 10 from memory). As you said, with no visible damage what should we advise. I see where the national chains are coming from advising 5 years (good for sales figures too). I recently checked the date of a pair of odd size tyres we brought from a well known supplier & they were already 4 years old!