Threshold

When an inspector walks around a returned lease car with a clipboard and a gauge, they are not judging damage by eye -- they are measuring it against a published list of size thresholds. The BVRLA Fair Wear and Tear guide gives each common defect a numeric cut-off in millimetres. Below the threshold, the mark is accepted as ordinary use. Above it, the defect is written onto the inspection report as a rechargeable item.

The word can mean other things on a car -- people sometimes call the sill plate under the door a "door threshold" -- but in the leasing world "threshold" almost always means the BVRLA size limit, not a body panel.

What it means

A threshold, here, is a numeric line in the sand. The BVRLA guide lists, for each type of defect, a maximum size and often a maximum count per panel. A scratch on the surface of a vehicle which is less than 25 mm in length and does not penetrate to bare metal is acceptable. A dent of 15 mm or less, paint unbroken, up to two per panel, is acceptable -- but roof dents and dents on a swage line are excluded regardless of size. A stone chip up to about 3 mm that has not rusted is acceptable, within per-panel limits (typically four per panel, more on forward-facing panels and door edges). Tyre tread must be above the legal 1.6 mm. Every one of those figures is a threshold: cross it, and the fair wear and tear presumption falls away.

Thresholds differ by defect type

There is no single threshold; each defect type carries its own rule, and the rules are not interchangeable. A scratch is judged on two things at once: length, and whether it has broken through to primer or bare metal. A 20 mm scratch you can feel with a fingernail but that has not cut through the clear coat is usually fine; a shorter scratch that has gone to metal can fail because of depth rather than length. Dents are judged on diameter and on whether the paint has cracked, with location overriding everything: a 10 mm dent on a flat door skin may pass while the same dent on the roof or along a swage line does not. Chips are judged on size, count and rust; a clean 2 mm chip is nothing, the same chip with a rust halo is a fail. Tyres are the simplest of the lot -- a single number, 1.6 mm, measured across the central three-quarters of the tread, with cuts, bulges and kerb-scuffed sidewalls assessed separately. Knowing which axis applies to which defect is half the battle: people fixate on length when the real problem is depth, or on a single big chip when it is the cluster of small ones that tips the panel.

Why it matters

Whether a mark costs nothing or triggers a SMART-repair charge comes down to a few millimetres -- a 24 mm scratch is fair wear; a 26 mm scratch is a recharge. Modern inspections use a credit-card-sized damage gauge or a ruler, not eyeballing, so a pre-return walk-round done only by eye will miss defects that cross the threshold on paper.

Count matters as well as size. Most thresholds carry a per-panel maximum: four 3 mm chips on a bonnet may be acceptable; the fifth tips the whole panel out of the guide even if every chip is individually under size. Location also overrides size -- roof panels, swage lines and forward-facing panels carry tighter thresholds or zero-tolerance rules, so size alone is not a green light. All of this makes pre-return prep threshold-driven: a good end-of-lease prep drags borderline defects back below the line. A 30 mm scratch polished down to 20 mm drops from chargeable to acceptable.

How inspectors measure against the threshold

The tool that decides most cases is unglamorous: a credit-card-sized damage gauge with cut-out windows and printed size limits, or a plain steel rule. The inspector lays the gauge against the mark, reads the length or diameter off the printed scale, and writes the figure down. A tread-depth gauge does the tyres. The whole point of the gauge is to take opinion out of it -- the inspector is not deciding whether a scratch looks bad, they are recording whether it fits through a 25 mm window. Most return inspections are also photographed, with a reference object or the gauge itself in shot, so the measurement can be audited later if you dispute the charge. That is why arguing "it's only a small scratch" rarely works: there is a photograph with a ruler next to it. The flip side is useful to you -- because the method is mechanical and repeatable, you can run exactly the same check yourself before the car goes back, with the same kind of gauge, and get the same answer the inspector will.

Where you will see it

You will see the word on pre-inspection checklists, BVRLA guide PDFs, leasing-company driver packs and end-of-lease inspection reports. Typical wording: "scratch exceeds 25 mm threshold", "dent above acceptable size", "chips within threshold -- no charge", "wheel kerb damage -- threshold exceeded, refurbishment required".

When you are borderline

The interesting cases are never the obvious ones. A door dented to the size of a fist is going to be charged and everyone knows it; the cases that matter are the ones sitting a millimetre or two either side of the line, because those are the ones a couple of hours of work can move. Tom, our operations manager, treats a pre-return car as a sorting job: every mark goes into one of three piles. Comfortably under the threshold, leave it -- spending money to improve a mark that already passes is wasted. Comfortably over, and only a proper repair will help. The middle pile -- the borderline marks -- is where the decision lives, and it is almost always worth acting on, because the cost of nudging a defect back under the line is far less than the recharge for leaving it over.

We had a three-year-old estate in recently with a scratch across the tailgate that measured a shade over 30 mm and had not gone through the clear coat. On paper that is a chargeable defect; the recharge quoted on a similar car had been the better part of a hundred pounds plus an admin fee. A machine polish brought it down to a faint mark well under 25 mm in under half an hour, because the damage was in the lacquer, not the colour. That is the whole economics of borderline work: the marks that respond to a polish are the ones still living in the clear coat, and they are exactly the ones the gauge will catch as just-over. A scratch that has cut to metal will not polish out, but it also would not have been borderline -- it would have failed on depth long before length came into it.

Knowing where you stand before hand-back

The reason a pre-return inspection is worth doing is not that it fixes anything; it tells you which pile each mark is in before the money is on the table. Walk the car in good light with a gauge, measure rather than glance, and note every mark with its length or diameter and whether it has broken the paint. Count the chips per panel rather than waving a hand at "a few stone chips". Check the roof and the swage lines specifically, because those are where location beats size and an otherwise innocent dent becomes a fail. Do the tyres with a proper gauge, all four, across the centre band. What you end up with is the same list the inspector will produce, drawn up while you still have time to act on it -- and that is the difference between being surprised by a recharge sheet and having already decided which marks were worth taking back under the line.

Common mistakes

• Confusing this inspection "threshold" with the structural door threshold or sill plate -- they are unrelated.
• Judging defects by eye instead of measuring them; a scratch that "looks small" can still be 30 mm long.
• Ignoring the per-panel count rule: lots of sub-threshold chips can still fail a panel.
• Assuming thresholds are the same everywhere -- individual funders sometimes publish tighter internal standards on top of the BVRLA baseline.
• Leaving borderline marks untouched rather than polishing or SMART-repairing them back below the size limit before hand-back.

Authored by Danny Argent. Reviewed by Gary Wray. Last updated 10 June 2026.