Used car mileage: how many kilometres is too many?

There is no threshold beyond which a car has "too many" kilometres. Mileage should be judged against the car's age, its engine and above all its maintenance: a car with 150,000 km and every invoice is often a better buy than a car with 60,000 km and no history. What matters is knowing which parts reach the end of their life at the mileage shown, and whether they have already been replaced.

What mileage is normal for the car's age?

To estimate running costs, our guides use a profile of 12,000 km a year. It is a benchmark, not a rule: an 8-year-old car with 100,000 km is average, while a 3-year-old car with 90,000 km has covered a lot of ground, probably on motorways.

Both kinds of gap need an explanation:

• Very high mileage for the age. Often motorway driving, which causes little mechanical wear, but sometimes taxi, ride-hailing or company-fleet use. Ask about the type of journeys and for the invoices.
• Very low mileage for the age. A car that has barely been driven is not necessarily a bargain: short trips from cold, a strained 12 V battery, tyres and hoses that age even without being used. And an abnormally low reading should make you think of odometer fraud (see below).

At what mileage do the big expenses come?

That is the real question. Our model and engine guides show, when sources document it, the mileage at which problems appear. A few examples:

The logic is always the same: if the car is close to or past the due point of an expensive part, ask for the invoice for its replacement. If there is none, the cost of the job should come off the price (see how to negotiate).

Diesel, petrol, hybrid, electric: do the benchmarks change?

Yes, because wear does not concentrate on the same parts.

• Diesel. The bottom end is often considered robust (that is the case for the 1.6 TDI in our guide), but the emissions equipment (EGR valve, particulate filter, AdBlue) copes badly with town driving. Our guide to the Dacia Logan II places clogging of the 1.5 dCi's EGR valve and particulate filter between 120,000 and 180,000 km. A high-mileage diesel used mostly on open roads is often in better shape than a low-mileage diesel used in town. Our diesel or petrol article goes through the numbers.
• Petrol. Recent small turbo engines have their own weak points, regardless of mileage: the wet timing belt of the 1.2 PureTech and the 1.0 EcoBoost, oil consumption on the 1.2 TCe. On the 1.0 SCe, oil consumption is possible beyond 80,000 km, and the valve clearance is adjusted every 100,000 km.
• Toyota hybrid. The hybrid system has a reputation for durability, but our guide to the 1.8 hybrid reports head gasket failures on Prius 3 and Prius+ cars with more than 200,000 km, and wear of the traction battery on older examples. See also the most reliable hybrid SUVs.
• Electric. Mileage matters less than the state of the battery: a state-of-health (SOH) certificate tells you more than the odometer. Everything is explained in our article on the battery of a used electric car.