Build vs buy is the decision a business makes between commissioning custom software (build) and adopting an existing commercial product (buy). The question shows up every time a workflow needs a tool, and the right answer depends on fit, total cost of ownership, strategic value and how much you care about owning the system.
The honest framing in 2026 is that the build option has become cheaper relative to buying. AI-assisted development has dropped the cost of a custom build by 60% to 80% versus 2022. Many workflows that would previously have been forced into a SaaS that did not quite fit are now economically buildable.
Real recent examples. A multi-practitioner clinic looked at Cliniko (£100 per practitioner per month for 6 practitioners, so £7,200 a year) and a custom booking and clinical-notes system (£18,000 one-off plus £150 per month hosting). Build paid back in 30 months versus buy. A wholesaler looked at Sage 200 plus a stock add-on (£2,500 a month all-in plus implementation) versus a custom stock-and-rebate system (£25,000 plus £400 per month). Build paid back in 14 months versus the SaaS run-rate. A recruitment agency looked at building over Bullhorn versus the SaaS itself. Buy won; the custom build had no commercial advantage.
When the SaaS market has nothing that genuinely fits (you have tried two or three options). When the workflow is core to your competitive advantage and you do not want it on the same platform as everyone else. When integration to your other systems is the value, and the SaaS will not integrate cleanly. When total cost of ownership over 3 to 5 years tips clearly toward the build. When you want to own the system fully, including the data, the deployment and the future direction.
When a SaaS fits 80%+ of your workflow and the workarounds for the missing 20% are bearable. When the workflow is not strategic to your business (HR system, payroll, generic CRM, generic accounting). When the SaaS vendor is investing in features faster than you would build them. When the total cost of ownership over 3 to 5 years tips clearly toward the SaaS. When the implementation risk of a custom build (timeline slip, scope creep, wrong choices) is higher than the cost of compromise on the SaaS.
Digital Signet will tell you to buy if buying is the right answer. We will tell you to build if building is. The conversation is free and the analysis is the same shape: name the workflow, name the SaaS options you have evaluated, name what they cannot do, run the build cost versus the SaaS run-rate over 3 years, name the strategic factors. If you arrive at "build" we scope and fixed-quote the build (app builds or AI implementation). If you arrive at "buy" we will not make a penny from the conversation and will sleep fine. The longer guide on Sheets-vs-replacement, which is the most common form this question takes, is at Google Sheets automation.
Facing a build-vs-buy decision? Send us the SaaS options you are considering and the gaps you have hit. We will give you an honest read on which way the maths and the strategy point.
Email oliver@digitalsignet.com