Clients ask for a fixed price because they want certainty. We can give them certainty about the work we have agreed on, and we cannot give them certainty about work that has not been defined yet, no matter how the contract is worded.
The number is only as good as the scope beneath it
A fixed price attached to a vague scope is not really fixed, it is a starting point for a negotiation about change requests. A fixed price attached to a written scope — the same document we produce from discovery — is a real commitment, because both sides can point at the same page when something is disputed.
What we fix and what we don't
- Fixed — the features described in the scope document, to the acceptance criteria written alongside them.
- Fixed — the timeline for that scope, with the milestones that make progress visible along the way.
- Not fixed — anything raised after the scope is signed that was not in it. That is a change request, priced separately, and it is not a failure of the process — it is the process working.
Why "just build it and we'll sort out details" is expensive for everyone
Details are where the cost lives. A feature described as "user profiles" might mean five fields or fifty, might mean public visibility or private, might mean one photo or an album. Every one of those decisions changes the estimate, and discovering them mid-build means either absorbing the cost silently — which teaches clients that fixed prices are not really fixed — or renegotiating constantly, which is exhausting for everyone and looks like bad faith even when it isn't.
A fixed price is a bet on a shared understanding of the work. Discovery is how you make sure both sides are betting on the same thing.
What happens when scope genuinely needs to change mid-project
It happens, and it is not a problem provided it is visible. We keep a running change log next to the original scope, priced and dated, so at the end of the project nobody is surprised by how the final number diverged from the first one — they can see exactly why, line by line.
The trust this builds
Clients who have been through this once tend to invest more in discovery the second time, because they have seen that the number at the end matched the number at the start, for the scope that was actually agreed.