Here is a job that looked fine on paper and lost money in the real world.
Quoted at $18,000. Priced properly, decent margin, won on the strength of the quote. Then on site the client asked if you could move a couple of points while you were in the wall. Sure. Then the old switchboard turned out to be worse than it looked, so you did the extra work rather than stopping the job for a week. Then they asked for two more downlights in the hallway and you said don't worry about it. Then the plasterer was late, so your bloke sat around for half a day and you wore it.
None of those decisions was wrong on its own. Every one of them was the kind of thing a good operator does. Add them up and the job that was quoted at $18,000 delivered the margin of a job quoted at $14,500, and nobody in the business could tell you exactly where the missing $3,500 went, because it never appeared anywhere as a number. It just quietly wasn't there at the end.
This is the single most common way profitable-looking trade businesses end up unprofitable, and it is almost never a pricing problem. The price was right. The problem is that the job changed after the price was set, and the price didn't change with it.
Why good operators give work away
The instinct behind unpriced variations is a good instinct. You are on site, the client is standing there, the relationship matters, and the extra thing they've asked for looks small. Stopping to write a variation feels like being difficult about twenty minutes' work. So you absorb it, bank the goodwill, and get on with the job.
That reasoning holds up for one variation. It falls apart because it never is one. It is four or five per job, on every job, all year. And the goodwill you're buying is usually invisible to the client anyway, because they don't know you absorbed it. They asked, you said yes, they assumed it was included. You paid for a gift the recipient never received.
The second reason is timing. Variations get raised at the worst possible moment for a commercial conversation — mid-job, mid-mess, when the client is anxious and you're covered in dust and you both just want the thing finished. Nobody wants to talk about money there. So the conversation gets deferred until the final invoice, which is precisely where it becomes a dispute. The client has already mentally banked the quoted price. An invoice that arrives $3,500 higher than the number in their head doesn't read as fair payment for extra work. It reads as a blowout.
That is the trap. Charge for the variation at the end and you look like you're padding. Don't charge and you eat it. The only escape is to move the conversation earlier, before the work is done, when it's still a choice rather than a bill.
What the law already requires (and most people ignore)
If you do domestic building work in Victoria, this isn't just good practice. There is a legislated process, and it exists because unwritten variations cause so many disputes.
Consumer Affairs Victoria is direct about it: for a major domestic building contract, you and your client must agree in writing to the changes and put the details, including new price and completion date, in the contract before the work is carried out. The vehicle for that is a variation notice, signed by both parties. The threshold for a major domestic building contract in Victoria is $10,000, so this catches a very large share of ordinary residential work.
There is one sensible exception. A variation notice isn't required where the client requests a change and you reasonably believe it won't require a permit change, won't cause a delay, and won't add more than two per cent to the original contract price. Even then, Consumer Affairs Victoria recommends putting it in writing and having both parties sign.
Worth knowing the flip side too, because it's the thing that catches builders out: the client does not have to pay for variations ordered to deal with issues you should have identified before starting work. That is not a loophole to be angry about, it's a straightforward incentive to do a proper site assessment before you price. The variations you can charge for are changes to what was agreed. The ones you can't are your own missed scope.
Other states have their own regimes with their own thresholds and forms, so check your own jurisdiction. But the principle is identical everywhere, and it's the same principle that protects your margin whether or not the law is looking: written, priced, and agreed before the work happens.
Gold nugget. Price the variation process into the original quote, not just the job. Add one line to every quote: an hourly or per-item rate that applies to any work outside the listed scope, agreed at signing. Doing this changes the entire dynamic on site, because when the client asks for the extra downlights you are no longer negotiating a price in a hallway — you are applying a rate they already agreed to when they were calm, comparing quotes, and in a buying frame of mind. "That's outside scope, so it'd be two hours at the variation rate we agreed, call it $340 — happy for me to do it?" takes ten seconds and almost never gets a no. Negotiating the same number from scratch, mid-job, takes ten minutes and often gets a discount you didn't intend to give.
The two-minute version that actually gets used
The reason variation processes fail in trade businesses is that they're built for the office and the work happens on a site. If the process requires getting back to a desk, opening a template and emailing a PDF, it will be skipped, because the moment has passed by the time you're back in the ute.
So build it for the phone.
The whole process is: the client asks for something; you say yes, that's a variation, I'll send it through now; you send a message from where you're standing that names the work, names the price, names any delay, and asks them to reply confirming; they reply; you do the work. Two minutes, on site, while everyone is still standing in the room where the decision was made.
A text message that says "Extra 2 downlights in hallway — $340 inc GST, no change to finish date. Reply YES to go ahead" and a reply that says "yes" is a written record of an agreed variation. If your job management software generates a proper variation for signature on the phone, better again, and for regulated domestic building work you'll want the formal notice. But the enemy here is not informality. The enemy is silence. A confirmed text beats an unsigned intention every single time.
Then the second half, which is where most businesses fall down even when they do raise the variation: it has to reach the invoice. A variation that lives only in a text thread on one person's phone gets forgotten at billing. Whatever your system, the variation must land in the job file the same day it's agreed, so that whoever raises the final invoice can see it. If you're not sure your current setup can do that, that's a tech stack question worth answering before it costs you another quarter.
Gold nugget. Once a month, pull your last ten completed jobs and compare quoted value against invoiced value. You are not looking for an average — you are looking for how many came in at exactly the quoted number. On a healthy job book, a decent share of jobs should invoice above quote, because real jobs change. If ten out of ten invoiced at precisely the quoted figure, your team isn't running clean jobs, it's absorbing every variation silently. That single count tells you more about where your margin is going than any P&L will, and it takes about fifteen minutes.
This is a leadership problem before it's a paperwork problem
If you're the owner and you raise variations properly but your leading hand doesn't, the process doesn't exist. Blokes on site absorb extras because they think that's what good service looks like, and because nobody ever told them otherwise, and because saying no to a client feels like their problem rather than the business's.
So the instruction has to be explicit and it has to remove the personal awkwardness: you never have to say no on site, and you never have to negotiate. You say "that's outside what we quoted, I'll get it confirmed and then I'll do it," and you send the message. That framing lets the team stay helpful, which is what they want to be, while the business still gets paid. It's the same shift as any other system you hand over — the point is that the right thing happens whether or not the owner is standing there, which is the whole substance of moving from tradie to CEO.
And when you do this consistently for a quarter, something else usually becomes visible. If your jobs are constantly growing beyond scope, sometimes the variations aren't the problem — the original scoping is. Jobs that reliably need $3,000 of extras were probably quoted $3,000 light, which is a pricing conversation rather than a process one, and how to price your services so you actually make money is where that starts. Either way, you can't diagnose it until the variations are being written down, because until then the evidence doesn't exist.
The businesses that fix this don't become harder to deal with. They become clearer. Clients get told what things cost before they happen, which is what most clients actually want, and the final invoice never contains a surprise. You just stop paying for the privilege of doing extra work.
If you can't say what the gap is between what you quote and what you invoice, that number is usually worth more than any new marketing spend. Working out where the margin actually leaks is one of the first things we pull apart in the Business Health Check — a fixed-price review of your pricing, your numbers and your job costing, with a written plan of what to fix first. Or start with the free five-minute scorecard to see where you stand.