Guide
A three-question test to tell a genuine warranty callback from a billable job, with a script to use on the doorstep and the maths for pricing your workmanship window so it's a marketing spend, not a leak.
Every owner-operator has stood on a customer's doorstep for the second time, toolbag in hand, trying to work out whether this one is free. Get it wrong one way and you're doing unpaid work every week. Get it wrong the other way and you lose the customer, and probably the review, over what looks like a shakedown.
The fix is to stop deciding case by case and use a fixed test. Apply it the same way every time, say the same words every time, and the awkward conversation mostly disappears because the customer can see the logic.
Ask these three questions, in order, before you say a word about money:
Three yeses: it's free. One no, anywhere in that chain, and it's billable. That's the whole rule. It's deliberately binary, because grey areas are where you either bleed hours or start an argument.
Say this on the phone before you get in the van, so nobody feels ambushed at the door:
"I want to check something before I come out. Is this the same issue we sorted last time, on the same part? If it is, and we're within [90 days / 12 months] of that job, there's no charge. If it's turned into something different, or it's outside that window, it'll be a standard call-out at [£X]. I'll know for certain once I've had a look, but I wanted to be upfront."
This does two jobs. It sets the price before you arrive, so there's no surprise. And it puts the test into the customer's own words, so if it fails the test, they've already half-agreed with you.
Some situations fail the test automatically, regardless of timing:
None of these are "free with a discount." They're billable jobs. A discounted callback fee for a genuinely new problem trains customers to expect discounts for everything.
Workmanship failures aren't random over time. They cluster early. If you fit something badly, wrong torque, missed connection, bad seal, it tends to show up fast, usually within the first few weeks of use as the system cycles through its normal range a few times.
That's why 90 days is the industry-common floor for a workmanship warranty. It catches the overwhelming majority of genuine installation errors: the things that were wrong when you left, not things that wore out afterwards.
Push the window to 12 months and you're not really covering more installation errors, most of those already showed up in the first 90 days. You're covering general wear, product ageing, and customer handling, none of which is your fault. A 12-month warranty is mostly goodwill and marketing, not risk management.
That's not a reason to avoid offering 12 months. It's a reason to price it as the deliberate spend it is, rather than pretending it's free.
If a longer window is marketing, fund it like marketing: build the expected cost into your hourly rate rather than absorbing it as a surprise each time a callback lands.
A workable range is 1.5–3% of labour added across every job, not just the ones that end up needing a return visit. The percentage depends on your trade's typical callback rate and how long your window is:
| Workmanship window | Typical callback load | Suggested labour uplift |
|---|---|---|
| 90 days | Low, catches install faults only | 1.5% |
| 6 months | Moderate | 2% |
| 12 months | Higher, covers goodwill callbacks too | 2.5–3% |
Say your labour rate works out at £60/hour after you've run it through the hourly rate calculator. You decide to offer a 12-month workmanship warranty and fund it at 2.5% of labour.
New effective rate: £60 × 1.025 = £61.50/hour.
On a typical 4-hour job, that's £6 extra, spread invisibly across the quote. Do 300 billable hours a year at that rate and you've set aside £450 a year specifically to cover genuine callbacks and the odd goodwill visit, without eating into your margin or dreading the phone ringing.
Compare that to the alternative: no uplift, no reserve, and every callback either comes straight out of profit or gets fought over on the doorstep. The 2.5% is cheap insurance against both.
The three-question test only works if the customer knows the window exists before the callback happens. State it on the invoice: "12-month workmanship warranty: covers the part and fault fixed on this invoice only. Excludes customer-supplied parts and unrelated faults." One line, every invoice, no exceptions.
If you're building this out properly, a standard warranty clause, callback script, and invoice wording are exactly the kind of templates worth keeping in a single reference, which is what the small business operations kit is for. Write the rule once, apply it every time, and the awkward doorstep conversation stops being awkward.
The Small Business Operations Kit ($19) turns guides like this one into fill-in-once worksheets: rate card, quoting sheet, job costing, payment terms and follow-up templates. Built by the same people who write these guides.