I've only been RVing about 15 years, but I also repaired buses for our church for about that many years. It seems to me that regular driving that warms the tires up and gives them a workout helps prolong their lives. From reading here, it also seems that tires really harbor grievances. Drive over a curb, run over that big piece of junk in the road, that tire's gonna get even with a separation or blowout. Maybe not right away...
But I have a question about Tire Age. Limited Service Spares, so common in cars, minivans and so on. They may not leave the trunk for a decade. I can imagine they're formulated for Shelf Life not Tread Wear, but is that true? If I keep one inflated, can I count on it after a dozen years or so?