Stuart Totterdell
Technical Director
Your SaaS subscription costs £500 per month. Your custom automation project costs £30,000. The SaaS is obviously cheaper.
Except it is not. And the fact that most mid-market businesses make this comparison without thinking it through is one of the most expensive financial mistakes in modern operations.
The monthly illusion
SaaS pricing is designed to feel affordable. The number is small. It recurs monthly. It fits neatly into an operating expense line. Nobody needs to approve a capital expenditure. Nobody needs to build a business case. The procurement process is a credit card and a terms-of-service checkbox.
This is by design. SaaS vendors know that a £500 monthly commitment is psychologically easier to approve than a £30,000 one-off investment - even when the one-off investment is objectively cheaper over any reasonable time horizon.
At £500 per month, your SaaS subscription costs £6,000 per year. Over three years, that is £18,000. Over five years, £30,000. Over seven years - which is the average lifespan of an operational process in a mid-market business - that is £42,000.
And that is before price increases. SaaS vendors typically raise prices by five to fifteen percent annually. Factor in a modest eight percent annual increase and your £500/month subscription becomes £680/month by year five and £920/month by year eight. The total over eight years is not £48,000. It is closer to £62,000.
Your custom automation project cost £30,000. Once. It does not increase. It does not renew. It does not charge you per seat, per user, per transaction, or per API call.
What the comparison actually looks like
The honest comparison is not monthly cost versus upfront cost. It is total cost of ownership over the useful life of the solution.
For a SaaS platform, total cost of ownership includes the subscription fee (including annual increases), per-seat costs as the team grows, add-on modules and premium features that were not included in the base price, data and systems integration costs (because SaaS platforms rarely connect to your existing systems without work), the ongoing cost of adapting your processes to fit the vendor's workflow (rather than the other way around), and the cost of extracting your data if you ever want to leave.
For custom development and build, total cost of ownership includes the upfront build cost, hosting and infrastructure (typically modest for mid-market scale), maintenance and updates (which can be scoped and budgeted), and the cost of changes as your business evolves.
When you lay these out side by side over a five-year period, the custom build is frequently cheaper. Not marginally. Significantly. And it comes with something the SaaS never provides: you own it.
The per-seat problem
SaaS pricing models are designed to grow with your business. That sounds positive. It is not.
Per-seat pricing means that every person who needs access to the system increases your cost. Hire five more people in the operations team and your monthly bill goes up. Give the finance team read access to the reporting module and your monthly bill goes up. Allow a client to access a portal and - depending on the vendor - your monthly bill goes up.
Your business is penalised for growing. Your cost increases with headcount, not with value. The vendor benefits from your success. You just pay more for the same software.
Custom automation does not charge per seat. It does not charge per user. It does not charge per transaction. The system costs what it costs to build and run. Whether five people use it or fifty, the cost does not change.
What SaaS actually costs when you add the hidden lines
The subscription fee is the beginning, not the total.
Most mid-market SaaS implementations require integration work - connecting the new platform to the ERP, the CRM, the finance system. That integration is not included in the subscription. It is a separate project, often delivered by a third party, and it typically costs as much as the first year of the subscription itself.
Then there is customisation. The SaaS platform works a certain way. Your business works a different way. The gap between those two is bridged by configuration, custom fields, workaround processes, and - frequently - manual effort. The cost of adapting your operation to fit the vendor's model is real, recurring, and almost never included in the procurement comparison.
Then there is lock-in. Once your data is in the platform, your processes are built around it, and your team is trained on it, switching costs are enormous. The vendor knows this. It is why they can raise prices annually with confidence. Where are you going to go?
What custom costs when you add the real numbers
Custom automation has a clear upfront cost. It also has ongoing costs - hosting, monitoring, occasional updates. These are real and should be budgeted.
But they are predictable. They do not increase because you hired someone. They do not increase because the vendor decided to raise prices. They do not increase because you want to give another department access.
And the build itself produces an asset. A piece of infrastructure that your business owns, that sits on your balance sheet, that can be depreciated, and that continues to deliver value long after the build cost has been absorbed.
A SaaS subscription produces nothing. When you stop paying, you have nothing. No asset. No infrastructure. No intellectual property. Just a login that no longer works.
When SaaS makes sense
SaaS is not always the wrong choice. For commodity functions - email, calendar, file storage, basic project management - SaaS is efficient, well-maintained, and appropriately priced. Nobody should be building a custom email client.
SaaS also makes sense when the process it supports is genuinely standard - when your business does it the same way every other business does, and the vendor's workflow fits without adaptation.
But for core operational processes - the ones that differentiate your business, that handle your specific data, that follow your specific rules - SaaS forces you to rent a generic solution that was not designed for you, adapt your operation to fit it, and pay for it every month forever. This is where tech consultancy that is not selling you the platform earns its fee.
For those processes, the maths points somewhere else entirely.
The question your CFO should be asking
The question is not "how much does the SaaS cost per month?" The question is "what is the total cost of this solution over five years, compared to building what we actually need?"
When that comparison is made honestly - including price increases, per-seat growth, integration costs, and the value of owning an asset versus renting a subscription - the custom build wins more often than most businesses expect.
Not always. But often enough that the comparison should be mandatory. And in most mid-market businesses, it is never done.
