You quoted a bathroom. On day three she asks whether you could put a shaver socket in while the wall’s open, and swap the towel rail for the taller one she’s just seen. Both sound like nothing. Between them they’re most of an afternoon, a trip to the wholesaler and a socket you now need to test and certify.

Nobody argues about the big changes. It’s the run of small ones that nobody priced, nobody wrote down, and nobody mentioned again until the final bill. This is about the changes that turn up during a job — how to price them, how to get a yes before you start, and how to keep a record so the last invoice holds no surprises.

First, work out which kind of change you’re looking at

Every mid-job change falls into one of three buckets, and they’re not treated the same.

The customer has asked for something extra. A shaver socket, an extra downlight, a better worktop, tiling the whole wall rather than the splashback. Clearly chargeable, clearly a variation. Price it and agree it.

You’ve uncovered a condition nobody could see at survey. Rotten joist ends under the bath, no insulation where the drawings said there was, a soil pipe running exactly where the units go. Also chargeable — provided you flagged the possibility rather than promising a firm price on something you couldn’t see. If you priced a provisional sum or wrote “subject to opening up” into the quote, you’ve already had that conversation once and this is just the follow-up. If you didn’t, it’s a much harder sell, which is the whole argument for pricing honestly around what you can’t see.

You got your own price wrong. The job’s exactly as described and you’ve simply underestimated it. That isn’t a variation — it’s tuition. Honour the fixed price you gave, finish it properly, and change how you price next time. Dressing up your own mistake as an extra is the fastest way to lose a customer who was otherwise going to recommend you.

Be strict with yourself about which bucket you’re in. Customers can usually tell, and the ones who can’t will ask someone who can.

The golden rule: price it, get a yes, then do it

Every variation gets priced and agreed in writing, before the work happens. Not at the end of the week. Not on the invoice.

Once the work is done, the customer has lost the only real choice they had — to say no, or to say “not at that price”. Presenting it afterwards makes you the person who spent their money without asking, even when the work was genuinely needed and fairly priced. You end up either knocking it off to keep the peace or getting paid late by someone who feels stung.

“In writing” is not a formal document. A text message is a written record, and it takes thirty seconds standing in the room:

Hi Dave — while the floor’s up I can see the pipework to the rad needs rerouting to clear the new unit. That’s about half a day plus fittings, £180 (illustrative — your number will differ). Happy to crack on if you give me the nod. If you’d rather leave it, the unit will have to sit 40mm forward of the wall.

That message does four things at once. It explains the problem, gives a price, asks permission, and states the consequence of doing nothing. His “yes go ahead” back is your authority and your evidence.

Three scripts for the moments that actually come up

The small addition, asked on the spot.

Yes, easily done. It’s an extra £X — shall I add it in? I’ll pop it in a text so we’ve both got it.

Say the price in the same breath as the yes. Trades get burnt by pausing, saying “leave it with me”, then trying to raise money two days later when it’s already fitted.

The concealed problem. Stop, photograph it, then message before you touch it.

Hi [Name], I’ve hit something I need to check with you before I go further. [Photo.] [What it is and why it can’t be left.] To put it right is [£X] and around [half a day], which will push the finish date to [day]. Let me know and I’ll get on with it.

Stopping feels dramatic. It is far less dramatic than doing it and explaining later.

The customer who assumed it was included.

Ah — I can see why you’d think that. It’s not in the quote; what I priced was [read the line back]. I can absolutely do it, and it’s [£X] on top. Want me to add it?

No arguing about what was fair. You read the line, you offer the fix, you price it. If you find yourself having that conversation on most jobs, the problem is upstream in how the scope is written before you start, not in the customer.

Price the extra properly — don’t quietly discount it

The standing temptation is to price variations soft because you’re already there and it feels awkward to charge full rate for something small. Being on site genuinely does remove travel, setup and a survey visit, and it’s fair to pass that on. Everything else still costs what it costs.

Two things to watch:

Small jobs carry disproportionate overhead. A twenty-minute task can eat an hour once you’ve fetched the bits, moved your gear, done it, tidied up and tested. Price the disruption, not the task.
Materials don’t become free mid-job. A special trip to the wholesaler, a part-box of tiles you can’t return, a fitting on next-day delivery — all real cost, all yours unless you charge it.

An illustrative shape for a single variation, and your numbers will differ:

Line	Illustrative
Labour — 0.5 day @ £260/day	£130
Materials (socket, cable, accessories) + markup	£46
Additional testing and certification	£35
Variation 3 total	£211

Give one number and one sentence of explanation. A homeowner doesn’t need your build-up; they need to know what it costs and that it isn’t plucked from the air.

Keep a running variations log

The final bill should hold nothing the customer hasn’t already seen and said yes to. That means keeping a list as you go, not reconstructing it from memory on a Sunday night.

Number them and record six things:

No.	Date	Change	Requested by	Price	Agreed
V1	14/03	Shaver socket to left of mirror	Customer	£95	Text 14/03
V2	15/03	Reroute rad pipework to clear base unit	Site condition	£180	Text 15/03
V3	17/03	Tile full wall instead of splashback	Customer	£240	Email 17/03

Then put the same numbered lines on the invoice, underneath the original quoted total. The customer reads it, recognises every line as a conversation they had, and pays. That’s half the reason a clear paper trail also gets you paid faster — there’s nothing left to query.

The “while you’re here” jobs

Not every favour needs an invoice. Tightening a loose handle or re-siliconing a bath edge on your way out costs five minutes and buys genuine goodwill — that’s not scope creep, it’s good business, and you should keep doing it.

The line to hold: a small kindness you choose to give is fine, an unpriced half-day is not. The tell is when you start dreading the next request, or working Saturday to catch up on things nobody paid you for. At that point say so plainly — “happy to sort that, but it’s a proper bit of work rather than a five-minute job, so it’ll be £X” — and mean it.

Build the process in before you need it

All of this is easier if the customer agreed to it when they accepted the quote. Two short lines do it.

On the quote, next to your exclusions:

Any work outside the scope above, whether requested by you or arising once work is underway, will be priced and agreed in writing before it is carried out.

And in your terms and conditions, a matching clause covering how variations are priced and when they’re payable.

With that in place, you’re never negotiating from scratch mid-job. You’re following a process you both signed up to — which makes the conversation administrative rather than awkward.

The takeaway

Decide which of the three buckets a change belongs in, and be honest when it’s your own pricing error. Price every genuine variation, send it in a message, and wait for the yes before you start. Charge properly for small work, keep a numbered log as you go, and show those lines on the final invoice.

Do that and extras stop quietly eating your margin and start being what they should be: profitable work you were asked to do.

Queezy turns a variation into the same clean, itemised PDF as the original quote — so what you send for the extra looks as professional as the job it’s attached to. Download it free on iPhone.

Handling Extras and Variations Without Losing Money