Tires on a motorhome should be changed every five years. But it is your life, some like to go ten years.
My coach come with Michelins XRV's 22.5 tires and I really never had a blow out, but at five years they all of a sudden had cracks all over the side walls. Since the XRV tires were mainly manufactured for motorhomes to give them a softer ride, it also tells me that those tires are not as strong as some other brands. So I switched to Toyo tires and I was impressed with the smooth ride they gave me, so when five years were up I bought another set of Toyo tires 16 ply and again balanced with Equal powder has given me the best ride that any person can ask for. And Toyo tires do not cost as much as Michelins.