There's no single trustworthy age-by-fault table
No official table says "at year X, component Y breaks". DVSA publishes MOT failures by defect category across the whole fleet. It never breaks them down by vehicle age.
Some sites dress up their own reprocessing of DVSA's raw open data as though it carried DVSA's authority. Those versions don't even agree with each other.
Three things are safe to say. DVSA's own data shows which components fail MOTs most often, UK-wide, at any age. A genuine independent survey from Which? shows how reliability and running costs shift across three age brackets, and the shift is smaller than most people assume. Some wear items have well-established lifespans that depend more on age than mileage.
Does a car really get less reliable with age?
Not by much. Which?'s Car Survey (fieldwork April-June 2025, 63,334 drivers reporting on 72,470 cars) splits cars into 0-4, 5-9 and 10-15-year age bands. The breakdown rate rises from 11% for cars aged 0-4 years to 12% for cars aged 10-15 years. That's a real difference, but it's a long way short of what the "old car = money pit" assumption suggests.
Average repair cost rises from £365 to £377 across the same brackets. Servicing costs less for the older bracket, at £290 against £318.
Which? also found well-maintained older models beating near-new cars outright. Some models over 10 years old had zero reported breakdowns in the past year, and repair times far below their age bracket's average. So age alone is a weak predictor of reliability. How a specific car has been looked after matters more.
0-3 years — still under warranty, low-fault years
Little goes wrong in this window. Most of what does is covered by the manufacturer's warranty. Our guide to used car warranty options covers what's usually still in place at this age. The first MOT test isn't due until a car turns three years old.
Newer doesn't mean trouble-free, though. A HiQ Tyres & Autocare survey found roughly one in five cars aged five or under failed their first MOT. That's HiQ's own survey data rather than a DVSA or government figure, so read it as an indicator rather than a hard statistic.
4-7 years — warranty expiry and the first wear items
Manufacturer warranty cover usually runs out somewhere in this window. The first genuine wear items start needing attention.
Batteries are a common example. RAC's own guidance puts a typical petrol car battery's lifespan at roughly 3-5 years. RAC puts a diesel's at roughly 4-6 years, since diesel batteries tend to be larger and work harder. Hybrid batteries commonly last 8-10 years, or 100,000-150,000 miles.
Brake pads, discs and tyres count as genuine wear items by now, not "new car" parts. First MOT advisories tend to appear on a car's record around here too. Our guide to MOT advisories explained covers what an advisory actually means and how seriously to take one.
8-12 years — running costs start to shift
This bracket straddles Which?'s 5-9 and 10-15-year survey bands. That's the honest guide for this age range. Nobody publishes an "X% of 10-year-olds need Y repair" figure worth quoting.
What does exist is the fleet-wide picture. DVSA's own data (FY2024-25) puts the overall Class 3 & 4 initial failure rate at 26.22%. The leading defect categories are lighting/electrical (10.89% of tests), suspension (8.73%), brakes (6.63%) and tyres (6.39%).
None of that is age-specific, because DVSA doesn't publish that breakdown. It's still a genuine, checkable picture of what goes wrong on UK cars generally, which beats an invented age-specific number.
Mileage shapes fault patterns as much as age does. A high-mileage 5-year-old and a low-mileage 15-year-old fail for different reasons. Our guide to mileage clocking and our companion piece on what mileage is too high for a used car go further into that side of the picture.
13+ years — keeping an older car on the road
By now the useful question shifts from "what breaks" to "what does it cost to keep going." Corrosion and general wear matter more across the fleet at this age. No official age-specific figure pins down how much more likely, so treat it as a well-established general pattern rather than a precise statistic.
Which?'s own 10-15-year data still shows well-maintained examples outperforming near-new cars. Age on its own isn't a verdict.
A full service history is one of the best predictors of which older car is a safe bet and which isn't. Our companion guide to what good service history looks like covers how to actually verify one rather than take a seller's word for it.
Cars this age are mainstream now, not fringe. SMMT's own data puts the average UK car at 9.7 years old, with 45.7% of cars on UK roads now over a decade old.
Age or mileage — which matters more?
Both, and they aren't the same thing. A low-mileage 15-year-old car and a high-mileage 5-year-old car tend to fail for genuinely different reasons. One suffers age-related wear on parts that degrade whether you drive or not, like rubber seals and batteries. The other suffers use-related wear on the clutch, brakes and suspension bushes.
Our guide to mileage clocking and our companion piece on what mileage is too high for a used car go deeper into the distinction.
How to check before you buy or keep an older car
Age brackets only take you so far. Our Comprehensive check gives you a specific car's complete MOT history, so you can read that car's own pattern of advisories and failures. On anything over about ten years old, I'd read the MOT history before I read the advert.
Then run our free check's running-costs estimator to budget realistically. It puts maintenance at around £300 a year across the wider UK fleet. That matters most on an older car, where maintenance costs are more likely to be front of mind.
FAQs
What breaks first on an older car?
No single official answer exists. But batteries, brake pads, discs and tyres are typically the first genuine wear items. They show up from around 4-7 years. Beyond that, DVSA's overall MOT data shows lighting/electrical, suspension, brakes and tyres as the most common defect categories across the whole fleet. That data isn't age-specific.
Is a 10-year-old car still reliable enough to buy?
Often, yes. Which?'s Car Survey found the breakdown rate rises only from 11% (0-4 years) to 12% (10-15 years). That's a real gap, but a small one. Specific well-maintained older models outperformed near-new cars outright. How well a car has been looked after matters more than its age alone.
Do cars really get less reliable with age, or is that a myth?
There's a real effect, but it's smaller than most people assume. Age on its own is a weak predictor. Service history and how the car's actually been looked after tell you more than the year on the registration plate.
Which matters more for reliability — a car's age or its mileage?
Both, for different reasons. Age-related wear on seals and batteries happens regardless of use, while mileage-related wear on brakes, clutch and suspension happens through use. A low-mileage older car and a high-mileage newer car fail differently, not necessarily worse or better than each other.
How much should I budget for repairs on an older used car?
There's no fixed figure. Our free check's running-costs estimator puts UK average maintenance costs at around £300 a year across the fleet. That's a reasonable starting budget. Push it up for an older car with a patchy service history.
How do I check a specific car's MOT and fault history before buying it?
Our Comprehensive check shows a specific car's complete MOT history. So you can see its actual advisory and failure pattern, rather than relying on general age-bracket guidance.