I bought two new tyres online for my caravan for delivery to a local fitting shop. I put the caravan wheels in the car and drove to the tyre depot. The new tyres were fitted with new valves and then balanced. The two removed tyres (which looked fine with good treads), rather than being put on the heap of scrap tyres, went straight on to the part-worn racks. My old tyres must have been at least 7 years old.