And if condition is equal?!

Will more miles done in less time mean less wear than less miles done in more time?!

Assuming condition and history are equal I’d favour the older low mileage example. It’ll be easier to sell on when you’re done with it

Surprised at that last bit. I thought "book value" and depreciation was mostly age-based.

Market economics aside, mileage inevitably involves some wear.

Deterioration due to age is less inevitable and varies a lot with usage, storage and particularly washing, BUT it should be mostly visible on inspection,

If they both look the same, mileage is your discriminating variable.

Above assumes you BELIEVE the mileage, however. I dunno what the situation is in The Yook now but when I lived there mileage was extensively faked and I never paid any attention to it.

The mileage can't be as extensively faked now that any car's MoT history is accessible online. Electronic odos are easily altered, but the annual sequence will show up any discontinuity.

So the quality of the miles traveled is what I was thinking of. Would not 10x one-mile journeys cause more mechanical wear than, say, 3x seven-mile journeys, even though the latter is over double the mileage?

Well, yes it might, but you are still making assumptions about how the car has been driven - unless you buy from the previous owner and can ask direct questions.

For two cars differing in age by 4 years to cost the same, the older one would need to be pretty special. Unless its annual mileage has been 2000 or less, a solid maintenance record should be encouraging.