Part lifespans, measured
How long car parts actually last
Data updated
Quick answer
Rather than a manufacturer's mileage claim, this is when each part starts failing the MOT across every car tested in Britain. Parts fitted for life — suspension bushes, springs, brake pipes, driveshaft gaiters — barely appear before eight years and climb steeply after twelve, exhaust system 104-fold. Parts replaced on a cycle — tyres, brake pads — fail at much the same rate at every age.
Failures per 100 tests, by car age
Every part, every age
| Part | 3–5 yrs | 6–8 | 9–11 | 12–14 | 15+ | Starts |
|---|---|---|---|---|---|---|
| Bulbs and lamps | 1.0 | 2.6 | 5.6 | 11.5 | 15.7 | 12–14 yrs |
| Suspension bushes | 0.6 | 2.4 | 6.4 | 10.8 | 12.9 | 12–14 yrs |
| Tyres | 6.3 | 6.7 | 7.7 | 9.0 | 8.6 | any age |
| Wiper blades and washers | 2.1 | 2.2 | 2.9 | 3.8 | 5.3 | 9–11 yrs |
| Coil springs | 0.2 | 1.5 | 3.2 | 4.5 | 3.7 | 9–11 yrs |
| Driveshaft gaiters | 0.1 | 0.6 | 1.3 | 2.1 | 3.0 | 12–14 yrs |
| Exhaust system | – | 0.2 | 0.8 | 1.6 | 2.5 | 12–14 yrs |
| Ball joints | 0.1 | 0.4 | 1.5 | 2.5 | 2.2 | 9–11 yrs |
| Brake pads and shoes | 1.4 | 2.4 | 2.4 | 2.5 | 2.0 | any age |
| Brake pipes | – | 0.2 | 0.5 | 1.2 | 2.4 | 12–14 yrs |
| Shock absorbers | 0.3 | 0.6 | 1.3 | 1.9 | 2.2 | 9–11 yrs |
| Brake discs | 0.5 | 1.0 | 1.5 | 1.8 | 1.7 | 6–8 yrs |
| Wheel bearings | – | 0.2 | 0.3 | 0.6 | 1.1 | 12–14 yrs |
| Brake hoses | – | – | – | 0.1 | 0.7 | 15+ yrs |
Bold marks each part’s peak. “Starts” is the first age band where the failure rate reaches half its peak; “any age” marks parts replaced on a cycle. Age bands correspond to registration years 2020–2022 through 2010 and earlier.
Common questions
- How is a part's lifespan measured here?
- By the age at which it starts failing the MOT, across every class 4 test in the DVSA dataset. Each part is mapped to the defects testers record for it, and those are counted per 100 tests at each car age. The result is not a mileage rating from a manufacturer but the observed curve of when British cars actually start needing the part.
- Why do tyres and brake pads show a flat line?
- Because they are replaced on a cycle rather than lasting the life of the car. A set of pads wears out every few years whatever the car's age, so the chance of a test catching worn pads is similar at three years and at fifteen. tyres and brake pads and shoes behave this way. The steep curves belong to parts that are fitted once and slowly wear or corrode.
- Which part wears out fastest with age?
- Exhaust system show the steepest climb: failures per 100 tests rise 104-fold between three-to-five years and their peak at 15+ years. Silencers and pipes rust through from the inside on short-trip cars; rubber hangers perish.
- Does this tell me when my part will fail?
- No — it tells you when parts of that kind start failing across the fleet, which is when to have yours checked. Your own car's mileage, how it is driven, where it lives and whether the part has already been replaced matter more than the average. The individual MOT history shows whether an advisory has been building.
Analysis built from DVSA data of