How long before replacing steering tires?

I have to report publicly that I've been very pleased with Michelin steering tires: Model XLEZ 275/80 R22.5.

I do general van freight in the Midwest - average weight 25K - steering axle receiving weight in the range of 11500 - 12200 lbs. I replaced them after 215 000 miles - 2.5 years. I bought the same pair.

They were still very much a smooth ride and a very good true shape and perfectly even wear - I do use centramatix rings - but the driver side tread depth being at 6/32 nds, would not promise much more usage and I don't feel like a sport of beating records with steering tires.

I still put them on the trailer and expect them to last there for at least another 90 - 100K miles.
Anyway, I recommend them as a verified good product.