A service contract answers a specific problem: a repair bill you did not plan for, and a car that stops working when you need it. Used-car buyers often feel a broader worry, which is that they do not know what the car has been through. A contract can pay toward some future repairs, but it cannot tell you what happened before you owned the car. So the first step is to work out which worry you actually have.
Ask whether you can list the car's history
Can you name the last major repair, the last timing or brake work, and the last time the car was in a shop? If the seller has receipts, read them. If the seller says there are none, you have learned something important, and that gap is information a contract cannot supply.
Ask what the title and records show
Check the title for any notation of prior damage, and check whether the number of owners matches what you were told. Ask whether the car has been serviced at more than a single shop and whether those shops kept records. Gaps in the paper trail are the signal to slow down.
Ask whether an inspection answers the question
An inspection by a mechanic you choose, working for you rather than for the seller, can tell you more about the car's condition than a service contract can. If the inspection finds trouble, a contract will not make that trouble disappear, and you may decide to walk away or renegotiate. If the inspection is clean, you have a clearer picture of what protection would actually be for.
Ask whether the worry is money or time
Separate the two fears. If the fear is a surprise bill, a contract is one way to soften it, and you can weigh the cost of the paper against the cash you have set aside for repairs. If the fear is being stranded or not knowing what is wrong, the better answer may be a sharper inspection, a car with fuller records, or a plan for getting around if the car is down. You are not obligated to buy protection just because a seller offers it.