The scariest number in a used car advert isn't the price. It's the mileage. For an enthusiast who knows what to look for, the car with six figures on the clock is often the smartest money on the forecourt.
Put a one and five zeros on the odometer and half the buyers scroll straight past, as if the car had been declared dead at 100,000 miles. The question is whether that fear is earned. The case here is simple: a car's history and maintenance tell you more than its odometer ever will. Then that case has to survive the best evidence against it, because some parts really do wear with distance, and resale really does punish big numbers.
First, scale. The RAC Foundation's analysis of MOT data put the average car under three years old at around 8,460 miles in 2024, and diesels at over 10,500. A three year old car with 60,000 on the clock hasn't been thrashed by default. It has most likely spent its life on motorways. Long, straight, boring miles.
Distance isn't care
An odometer measures distance. It doesn't measure care, and a car that sits, or only ever does short trips, has its own catalogue of problems. A diesel particulate filter needs a sustained run, roughly half an hour at 50mph or more, to burn off its soot. Deny it that and it clogs. Batteries that never get a proper charge give up early. Engines used only for short local runs may rarely reach operating temperature. Tyres harden with age, whatever the tread says, and brake fluid absorbs water over time, which is why many manufacturers want it changed every two years whether the car has moved or not.
Electric cars show it too. A study of MOT records found older, low mileage electric cars showing more friction brake defects than average. Regenerative braking meant the brakes were barely used, so the parts corroded instead. Low mileage didn't preserve them. Service schedules say the same: Ford's runs on 12 months or 12,500 miles, whichever comes first. The calendar wears a car as well as the road.
Someone else paid for the steep part
Carwow's sale valuations show the biggest drop arrives early. On average, a car past 20,000 miles was worth about a quarter less than the same car at 10,000. By around 100,000 miles, the curve flattens out. The six figure car has already done most of its depreciating, and the gap between it and a pristine example is real money: a set of tyres, a suspension refresh, a proper geometry setup, a few track days.
The free biography
The free MOT history service on GOV.UK shows every test result for a car in England, Scotland and Wales back to 2005: the mileage recorded each time, the failures and the advisory notes. You can see whether the miles climbed steadily or jumped around, and whether an advisory for a worn bush or a corroded brake pipe was fixed by the next test or quietly carried for three years. A seller can tell you a car was cherished. The MOT history tells you whether that's true.
The case against
Some things wear with distance however lovingly they're serviced: clutches, dual mass flywheels, suspension bushes and dampers, turbochargers, gearbox synchros. The national data backs it up. New AutoMotive analysed 47.4 million MOT tests for the BVRLA, the rental and leasing trade body. Petrol cars with 20,000 to 40,000 miles had a failure rate of 11.7%. Between 90,000 and 120,000 miles it was 22.1%, and above 120,000 it was 23.5%. Roughly double. Resale bites too. Fewer buyers want a 140,000 mile car, and if you need to sell quickly, the odometer will cost you at the exact moment you can least afford to argue.
Why the case survives
Even above 120,000 miles, more than three quarters of the petrol cars in that study didn't fail. For context, though it isn't like for like, the DVSA's own figures show just over 27.5% of all cars, vans and light passenger vehicles failed their initial MOT in the year to March 2026. The high miler isn't a wreck waiting to happen. It's a predictable list of jobs, done or due.
Distance wear is the most knowable kind of wear there is. You can ask whether the clutch has been replaced, read the receipt for the dampers and price the flywheel before you make an offer. What you can't easily price is the hidden damage of a car that sat in a damp garage on old fluids and cold starts. High mileage turns uncertainty into a shopping list.
And mileage fraud only runs one way. In 2019, HPI estimated that as many as one in fourteen cars in the UK had been clocked. Winding back an odometer isn't, in itself, an offence here. Selling a car without declaring its true mileage is. Nobody winds a clock forwards to make a car look worse, so the car to worry about is the suspiciously low mileage one with a thin file and a gap in its records.
A rule for buying one
A high mileage car is the smart buy when three things are true:
The MOT history climbs consistently, with no unexplained drops.
The big distance items are documented as done, or priced into your offer.
You'll keep the car long enough for the low price to do its work.
If any one of those fails, walk away or pay accordingly. If you need the car to be easy to sell next year, buy lower mileage and accept the premium. If the model has a notoriously expensive part that wears with distance and there's no record it's been dealt with, the odometer is telling you something. And if the miles in the advert don't match the miles in the MOT history, don't negotiate. Leave.
Mileage isn't a warning sign. It's a price. Buy the biography, not the number.
This article comes from an episode of the Auto Culture Society Podcast. New episodes every Wednesday: the podcast.