Annual mileage sets the pace at which a car reaches its odometer limits. Two cars of the same age can sit at very different readings. Fit the contract to the miles you drive each year, not only to the reading on the dash.
The long commute car
A car that drives long daily miles reaches the mileage limits sooner than its age suggests. For that car, the mileage line matters more than the age line. Ask how many years of coverage the contract gives at your yearly miles, and the odometer reading at which the mileage limit would stop it.
The second car in the household
A car used for errands and short trips may be old on the calendar but low on the odometer. Here the age line usually decides the question. Ask whether the contract still accepts the car once it passes the age line, even if the odometer reads low.
The shared car
When more than one person drives a car, the household should agree on who keeps the service records, who handles the paperwork, and who makes the claim call. Write those roles down. Ask whether the contract names authorized drivers, and whether a new driver in the household changes anything.
The move
A move to another state or province can change the rules a contract runs on. Ask whether the contract is valid where you will drive, and whether a move changes its terms or its claim route.
Match the term to the driving
Compare the contract length in years with the miles you expect to add. If the term ends on whichever limit comes first, the sooner limit decides the fit. Write your own estimate of yearly miles on a sheet and bring it to the quote. A seller can answer the fit question only when that number is in front of them.