Jim, I put 57,000 miles on my first set of Michelins on the '08 Dynasty and the tread looked like new (except for the steer tires when I had a bad alignment from Colton Truck in Colton, CA). Those tires were move to the tag and the tag tires moved to the steer. The tires reached their 7.5 yr. age limit so I replaced them. I can't imagine wearing out a set of tires unless you have alignment issues.
We now have 365's on the steer and tag with 315's on the drive axle. Prevost changed my front tires under warranty after 13 months as one or both were out of round (slight vibration). Those tires were listed on the invoice at $1,007 each. And, they performed a complete alignment too. I like warranties! (not extended warranties).
MM.