Every used car listing that's had at least one MOT test carries a history of advisories, and most buyers skim past them without really understanding what they mean. That's a mistake. Learning to read MOT advisory red flags properly is one of the cheapest, fastest ways to avoid buying somebody else's expensive problem.

An advisory isn't a fail. The car passed its test. But DVSA testers flag items that are close to needing attention, and the exact wording they use tells you far more than most buyers realise. "Slight wear" and "excessively worn" are not the same sentence, even though they sound similar to an untrained eye. One is a note for next year. The other is a car you should be negotiating hard on, or walking away from entirely.

This guide breaks down how to read advisory wording properly, which categories of advisory matter most, and when a pattern of advisories should make you reconsider the whole purchase.

Common MOT advisory red flags worth knowing

Some advisory categories come up again and again, and it's worth knowing what they typically mean before you're standing on a driveway trying to make a decision under pressure.

Tyre advisories are the most common and usually the cheapest to resolve; a full replacement set rarely runs past a few hundred pounds. Brake advisories deserve more attention, particularly wording like "pad thickness below reference" or "disc worn, pitted or scored", both of which mean parts and labour rather than a quick fix. Suspension advisories, especially anything mentioning a "corroded" or "deteriorated" component, tend to be among the most expensive to put right and are exactly the kind of thing our guide on MOT history and reliability by mileage explores in more depth.

Corrosion advisories deserve special caution. A tester noting "corrosion in close proximity to" a structural point isn't being dramatic; that phrasing exists specifically because DVSA guidance treats structural corrosion as a serious safety consideration, and it tends to worsen quickly once it's visible enough to flag. If you see this wording anywhere in a car's history, get a specialist inspection before you commit, regardless of how good the price looks.

Exhaust and emissions advisories are usually mid-tier in cost, though on newer cars they can point to expensive particulate filter issues rather than a simple pipe replacement. If you're weighing up a diesel specifically, our breakdown of diesel versus petrol reliability covers exactly this kind of failure pattern in more detail.