i have a friend who used to wrench for a Pro team & later the tour.
Since they had an unlimited supply of tires they changed pretty often.
They would pull the tires when they had any appreciable wear because why flat because of some small debris? I think they changed them about every week to ten days. Also they never reglue a tire so when they had a wheel repair it always got a new tubular. Time trial wheels always got new tires before the next stage just in case.
I was lucky they used to pile the tires in the team garage and since i was on the amateur squad we got as many "old" tires as we wanted. I got about 45 and the pile looked like it hadn't been touched...
ah the good old days