I tell my customers that high performance tires are only designed to work best for a season/year as far as the compound goes. Wear is another variable not directly controlled by the manufacturer. So a high end tire might not have a lot of miles but also might shows cracks during a greater number of miles year two.

I use Michelin Endurance4 tires but in black and find a couple of years on the rear is at most my expectation. This is about 1500 miles total (for any one rear tire) usually. I ride them on three different bikes. They do cut a touch more easily then other brands I've used as well as wear down faster. But they do have a nice ride feel and seem grippy enough for me.

What isn't known is the amount of time between actual manufacture and their being mounted for use. Tires can sit for many months on the few different shelves between the manufacturer and the rider and might see heat that we'll never know about. While it is a common feeling that a product life starts when it is bought and installed the reality is that some products do suffer wear/degradation before their sale. Batteries are another example of this. Andy.