A service contract runs for a set length of time and a set number of miles, and most contracts end at whichever limit is reached first. That makes the term a sizing question. Before you compare any two contracts, decide how long you actually plan to keep this car. A term that ends before your ownership does can leave you exposed, while a term that runs far past it may be coverage you never use.
Measure your real ownership horizon
Be honest about the plan. Is this the car you will drive until it is retired, or a car you expect to trade when the next job or household change arrives? Write down the number of years you think you will keep it, and add a margin only if you have a specific reason to expect a longer hold.
Check the mileage pace
Time is only half the limit. Take the odometer reading from your current paperwork, subtract the reading from the same point a year earlier, and multiply that gap by the years you plan to keep the car. Compare that total with the mileage cap in each contract. A car that drives little may hit the time limit long before the mileage limit, and a heavy commuter may hit the mileage limit first.
Ask what happens if you sell or lease out
If you may sell the car before the contract ends, find the transfer language. Some contracts can move to a new owner, and others end when the car is sold. A leased car also has its own end date, which is a separate question from the service contract's term, so do not assume the two line up.
Match the term to the plan, not to the longest offer
The longest term is not automatically the right one. Match the contract's end point to your plan, then check whether the paper still makes sense if you keep the car a little longer than you expected. For a car you expect to drive well past a typical mileage level, the providers that take high-mileage cars are a practical place to start, and the published figures in this site's tables are where to check each term.