Assessment of wear:

In a few cases specific tolerances are given e.g tyre tread depth, brake pad lining depth and movement in pins/bushes etc.  Most other situations require the tester to use their experience and judgement to decide whether:

1. The component has reached the stage where it is obviously likely to affect adversely the roadworthiness of the vehicle
2. The component has clearly reached the stage when replacement, repair or adjustment is necessary and
3. The component appears to break the law e.g broken rear lamp lens showing a light other than red to the rear.