When to build vs buy: a small business guide to custom software

How to decide whether bespoke software is worth building — with an honest look at costs, timelines, the 80% rule, and the middle-ground option most businesses overlook.

The question that saves you months of frustration

Every small business owner who wants to fix a broken process faces the same decision: buy an existing software tool, or build something custom? Get it wrong and you either spend months on a tool that doesn't quite fit, or you spend a year building something that turns out to be a bad investment.

Here's how we help our clients think through it.

Start with this question: how unique is your process?

Off-the-shelf software is built around how most businesses do something. If your process is similar to how most businesses in your sector operate, there's probably a tool that handles it well.

If your process is genuinely different — because you've innovated, because your industry is niche, or because your workflow cuts across multiple functions in an unusual way — then off-the-shelf tools will always feel like a slightly wrong-sized shoe.

The hidden costs of "good enough" software

Off-the-shelf software has obvious costs: the subscription fee. But it also has hidden costs that are easy to underestimate:

• Integration work — connecting it to your other tools often requires a developer or a platform like Zapier, adding time and cost
• Workarounds — the time staff spend working around limitations ("we just export to Excel and do it manually")
• Training overhead — off-the-shelf tools are built for general users; your team learns features they'll never use
• Licence scaling — per-seat pricing means costs grow linearly with headcount
• Vendor risk — the tool gets acquired, changes pricing, or discontinues a feature you depend on

When to buy: the clear cases

Buy off-the-shelf when:

• Your process is standard (CRM, accounting, email marketing, project management)
• You need to be live in days, not months
• You have fewer than 5 users and limited budget
• The problem is well-defined and unlikely to change significantly
• You're still figuring out your process and need to iterate quickly

When to build: the clear cases

Build custom when:

• Your process is genuinely unique and off-the-shelf tools cover less than 80% of your needs
• You have a large team and per-seat licensing will become expensive at scale
• The software is the product — you're building a SaaS business
• Data privacy or compliance requirements make third-party SaaS unsuitable
• You want a long-term competitive advantage from your internal tooling

The middle ground: automation + off-the-shelf

Many businesses find the answer isn't build or buy — it's "buy the core tools and automate the gaps." We connect your CRM, your project management tool, your email platform and your accounting software using n8n automations, creating a custom workflow layer on top of standard tools.

This approach typically costs 30–50% less than full custom development and can be delivered in weeks rather than months. It's often the right answer for businesses in the £500k–£5m revenue range who aren't yet ready to commit to a full custom build.

What custom software actually costs

We're a fixed-price shop, so we can be specific. Our projects typically fall into three ranges:

• Internal business tool (CRM, portal, dashboard): £8,000–25,000 depending on complexity
• SaaS MVP (multi-tenant, payments, user management): £20,000–50,000
• Full SaaS platform (enterprise features, API, white-labelling): £50,000+

Against these numbers, the question becomes: what is the broken process costing you per year in staff time, lost revenue, or competitive disadvantage? For most of our clients, the payback period is 12–24 months.

The decision framework in one question

If you had to summarise this into one question: "Is this process a competitive advantage, or just operational hygiene?"

If it's operational hygiene (invoicing, email, project tracking), buy the best off-the-shelf tool and move on. If it's a competitive advantage — something your business does differently that creates value for customers — it's worth considering whether a custom tool could make that advantage stronger, faster, or more defensible.