the.com/mileage

means The practical benefit or use you get out of something, often measured in how far it stretches before wearing out — literal distance traveled, or figuratively, how much value or leverage a thing still has.

from Built straightforwardly from 'mile' plus the suffix '-age,' which turns a unit into a measure or extent of it (compare 'tonnage' or 'footage'). It entered English in the 1700s-1800s to mean literal distance traveled or a travel allowance paid per mile. The figurative sense — 'getting mileage' out of a joke, an excuse, or a pair of shoes — is a later extension, treating any resource as if it were a vehicle with a finite number of miles left in it before it runs dry.