Five years and 30K on Michelin XRV 235R80 22.5
I retired from large trucking company after 30 plus years and spent a few of them in the tire shop. The company's findings. Tires are most prone to a flat from road trash after 50% wear. Now the "RV" verses any other tire has less tread depth. According to the representatives from Michelin and Goodyear, they make the tire with less depth for economical reasons ( theirs and ours both). Nobody likes to see an out of service tire with more than 50% tread still left.
Another failure point is the "Zipper". the side wall opens up like it was unzipped. Cause is over heating from under inflation. This can only be sometimes detected by visually inspecting off rim and with the aid off X-Ray like equipment. Too costly for RVers and only used when a tire is off rim for repair or recap. Tires can "peel" the tread due their built up construction. This again is caused from overheating, mostly low tire inflation. A tire in storage (parked in the driveway) will get the same UV rays as one rolling down the road. You can't stop the Ozone affect on the tire. Do not "dress" the tires to make them look pretty. Petroleum products are tires enemy. Do clean with soap and water. Don't over clean the tire. It is manufactured with "tire black" in it. The black migrates to the outer surface with use to help protect the tire from UV rays. Clean only when needed.Overloading the tire causes heat build up and the shortening of the life. Know what the "corner weights" are and lighten up the coach or it will cost you in the long run.
Don't change the tire height of the tire as it will affect the computer controlled aspects of the engine. The computer is expecting the height to be what the manufacturer told it that it was going to be.The best investment is a tire monitoring system and diligent response to the system. A warning of pressure loss means stop ASAP and find out why. Tires are built to take the increase in tire pressure from normal use. Don't worry about the increase. That is normal, the loss of pressure should raise the warning flag.