The proposal you sign covers the build. The number that decides whether any of it was worth doing shows up later, spread across small monthly charges and hours of upkeep that most quotes never mention. This page itemizes both — real magnitudes where they exist, and blanks where only your own books can fill them in.
Two ways to pay for the computing
Every AI feature runs on computing that you either rent by the request or own outright, and the two have opposite cost shapes.
Rented computing is a metered service. Each question the system answers costs a fraction of a cent to a few cents, depending on how long the question and the documents behind it are. A month of ordinary use for a small shop often totals less than a streaming subscription. The catch is that the meter never stops, and the bill scales with use — busy months cost more than slow ones.
Owned computing means a machine on your premises capable of running a private model: several thousand dollars of hardware up front, then electricity, and eventually replacement, because the machine ages whether you use it or not. The meter disappears. In exchange, you hold a depreciating asset.
Which shape is right depends on volume and on privacy. A dental practice or a law office that wants its records answered on hardware it controls has a reason to own. A contractor whose system sends a few hundred texts a month has no reason to buy a computer to do it. Anyone who quotes you hardware without asking about either factor is selling inventory, not fit.
The phone bill, itemized
The messaging side of these systems runs on utilities so cheap they are worth stating plainly. A text message costs on the order of a cent. A phone number rents for a few dollars a month. Call forwarding bills by the minute, in cents. Carrier registration — the paperwork US carriers now require before a business may send automated texts — adds small one-time and recurring fees.
Put together: a business that misses a hundred calls a month and texts every one of them back spends less on messaging than on one tank of diesel. So when a quote is large, understand what you are paying for. It is not the pipe. It is the design of the branch logic, the integration with the tools you already use, and the upkeep described below. That is legitimate work worth paying for — but it should be stated on the quote, not smuggled into a number you cannot inspect.
The maintenance line, named
This is the line item most quotes omit, and the one to insist on seeing.
Documents change. A supplier raises copper and the price book gets revised. A manufacturer bulletin lands in March and supersedes the fastener spec from last spring. The warranty terms pick up a new exclusions section in January. A system that answers questions from your documents answers from whatever it was last fed — feed it March, and it will answer from March in September, with complete confidence. Someone has to re-ingest the changed documents, retire the superseded versions, and spot-check that the answers moved.
Integrations break the same way. The platform on the other end of a connection changes its interface, a webhook stops firing, and leads quietly stop being written down. Nothing announces this; someone has to notice.
A realistic maintenance budget is measured in hours per month, not in zero. If a vendor's quote carries no maintenance line, that work is either unpriced — meaning you will pay for it later, at emergency rates — or it is not going to happen, and the system will rot quietly until the first embarrassing wrong answer. You would not expect a water heater to run for years with no service. This is not different.
Costs that rise when the thing works
A system that captures more calls sends more messages, holds more conversations, and writes more records. Those marginal costs are small. The cost that actually rises is attention: someone in your shop has to read the replies, return the calls the system flags, and log what became of each lead. If nobody owns that half hour a day, the cheap part of the system keeps running and the valuable part stops. Budget the attention alongside the dollars.
When the arithmetic turns against you
There are businesses this math does not favor, and it is better to know before signing anything. Below a certain ticket size and call volume, the fixed cost of maintenance outweighs anything recovered. If your average job is sixty dollars and you miss three calls a week, better posted hours or a person answering the phone is the cheaper fix.
For scale: HomeAdvisor's 2025 member-reported data puts an average plumbing job around $340, and Angi's 2026 cost guide puts a full HVAC replacement around $7,500. Those numbers are only there to show the range — never compute with an industry average. Compute with your own average ticket, off your own invoices, because that is the number the system has to beat.
And note what no worksheet prices: your own time changing habits. Reading the thread, calling back the landline callers, keeping the log honest. That cost is real, and only you pay it.
The worksheet
Fill this in from your books, not from anyone's slide deck.
On the cost side, monthly: messaging (missed calls × a few cents each), number rental (a few dollars), computing (a metered estimate, or hardware price divided by 36 months plus electricity), maintenance (expected hours × what you pay for skilled work), and your own attention, counted honestly in hours.
On the return side, monthly: recovered jobs × your average ticket × your close rate on quoted work.
If the cost column meets or beats the return column at honest numbers, do not buy — from this firm or any other. Nobody here will promise you a return, because nobody selling software controls your close rate or your season. What you can do is measure it yourself, which is a separate page on this site.
Where to start
Pull three numbers from your own records before you talk to any vendor: calls that rang out last month (your phone bill shows them), your average ticket from last quarter's invoices, and your close rate on quoted work. Everything else on the worksheet is arithmetic.