Yesterday, we had the rear tires changed on the Mh. The new Michelins 275x80x22.5. The old GY670s had no checks and the rubber was as supple as the day they were put on, with just some road dirt on ...
Wow, 13 yrs. on that set? The damage a blow-out can cause is worth a 7 yr. change-out to me. But, everyone has their comfort level.
It drives me nuts when you go into a store (any kind) that specializes in a product and they don't know what they are doing. You just want to slap them upside the head!