Plated racing shoes should be retired by the calendar, not the odometer

The foam doing the work stops doing it long before the outsole shows anything a runner would notice.

The old rule was five hundred miles and look at the tread. That rule was written for a shoe whose job was cushioning, made of a foam that compressed slowly and wore out visibly. It does not transfer to a modern racing shoe, and runners keep applying it anyway.

The mechanism in a plated racer is not cushioning. It is elastic return. A thick, very light, highly compliant foam takes the impact energy, stores a large fraction of it and gives most of it back, while a stiff plate manages how the foot rolls through and stops the toe joint bending as much as it wants to. The whole system depends on the foam still being springy. Not still being present. Springy.

Those two properties fail on different schedules. The foam loses resilience through repeated compression, through heat, and through simple ageing of the material, and it does this without changing shape much and without showing you anything. The outsole, meanwhile, is a thin piece of rubber that either wears where you land or does not. A shoe can look almost new, feel slightly less lively in a way the runner writes off as tired legs, and be returning noticeably less energy than it did.

There is a second effect worth naming. When the foam stiffens, the shoe does not simply get slower. It changes what it asks of the body. Part of the appeal of these shoes is that they reduce the work done by the calf and the ankle. A degraded pair quietly hands that work back, at the same paces, to an athlete whose ankle has spent six months not doing it. That is a plausible route to a calf or Achilles problem that arrives with no obvious cause.

So my rule, and I hold it firmly: log the date you first raced in them, count hard efforts rather than easy miles, and treat time on the shelf as real. A pair bought last season and worn twice is not a fresh pair.

I would also stop training in them entirely, which is not a popular position with anyone who has paid what they cost. Race in them, do a couple of tune up sessions in them, and let the rest of the mileage happen in something you do not have to trust.

You cannot see this failure. That is the whole problem.