Fixed price vs time & materials, honestly compared
Every agency will tell you their pricing model is the fair one. Here's the version with the incentives spelled out, including the ways both models get gamed — because we've seen both from the inside.
How each model actually works
Fixed price: you agree on a scope and a number. The agency carries the estimation risk. If it takes longer than they thought, that's their problem.
Time & materials (T&M): you pay for hours worked, usually weekly or monthly. You carry the estimation risk. If it takes longer, that's your problem.
That single sentence about risk is the whole comparison. Everything else is detail.
Where fixed price wins
- The scope is knowable. An MVP with a written spec, a marketing site, a defined integration — these can be estimated by someone who's built them before, so there's no reason for you to carry the risk.
- You have a hard budget. If $25k is what you have, a fixed quote is the only structure that respects that reality.
- You're comparing vendors. Fixed quotes against the same spec are comparable. Hourly rates are not — a $40/hr team that takes 3x as long costs more than a $90/hr team that doesn't.
How it gets gamed: the dark side of fixed price is the change-request machine. Some agencies bid low to win, then charge for every sneeze as "out of scope." Protect yourself: the contract should define scope in terms of user-facing outcomes ("a customer can subscribe, upgrade, and cancel"), not vague feature names, and it should state what a change request costs before you sign.
Where T&M wins
- The scope is genuinely unknowable. R&D work, untangling a legacy codebase nobody understands, or a product where the plan is to iterate weekly based on user feedback. Fixed-pricing discovery is dishonest — nobody knows the number.
- Long-running product work. Once you're past launch and the work is a continuous stream of improvements, T&M (or a monthly retainer, which is T&M with a haircut) matches how the work actually flows.
- You have strong technical oversight. T&M is safe when someone on your side reads the PRs and knows what a week of progress should look like.
How it gets gamed: slow-walking. Junior developers billed at senior rates, tasks that mysteriously take a sprint each, no pressure to finish anything. T&M without oversight is a subscription to someone else's payroll. Protect yourself: demand weekly demos of working software — not status reports — and a burn-rate projection against milestones.
The rule of thumb
Whoever is better positioned to estimate the work should carry the risk.
An experienced agency estimating a well-specified MVP is better positioned than you — so they should carry it, in a fixed price. Nobody is well positioned to estimate exploratory work — so pay as you go, in small increments, with the right to stop.
Why we default to fixed scope
We quote fixed prices for defined builds, and it's not altruism — it's that the incentives point the right way:
- It forces a real scoping conversation before money moves, which is where most project failures actually start.
- It makes us efficient. Our AI-assisted workflow means we build fast; under fixed price, that speed is our margin instead of our lost revenue. Under T&M, efficient teams literally earn less — think about what that incentivizes industry-wide.
- It makes the sales conversation honest. We can say "$18k, six weeks, here's exactly what you get" and be held to it.
When a project genuinely doesn't fit — discovery phases, legacy rescues — we say so and propose a short T&M engagement with a capped budget, whose output is usually a spec we can then fix-price. Scope the unknown cheaply, then commit to the known.
The model matters less than the incentives and the paper trail. But if an agency insists on T&M for a project they've built ten times before, ask them why you should carry a risk they're better equipped to price.
If you're scoping something like this, book a 30-minute call — we'll tell you which model fits your project and give you a straight answer on the number.