I get asked this question more than almost any other. A business owner has a problem, they know software can solve it, and they want to know whether they should build something custom or buy something off the shelf. It sounds like a simple question. It is not.
Over the last twenty five years I have been on both sides of this decision more times than I can count. I have built custom software for organisations like Wessex Water, Gridserve, Park Holidays and Defra. I have also built SaaS products like RealCube, Crocodile and CampSuite that are, by definition, the "buy" option for someone else. So I have a fairly balanced view on this, and my answer is almost never a straightforward yes or no.
Let me walk you through how I actually think about it when a client or a founder asks me.
Start with the real question
The build vs buy question is actually the wrong starting point. The real question is: does this software need to be a competitive advantage for your business, or does it just need to work?
If you are a logistics company and you need accounting software, buy it. QuickBooks, Xero, whatever. Accounting is not your competitive advantage. It just needs to work, be reliable and not cost a fortune. Nobody ever won a logistics contract because they had brilliant accounting software.
But if you are a logistics company and you need route optimisation software that integrates with your specific fleet management process and gives you an edge over competitors? That is a different conversation entirely. That might be worth building.
When I was working with Wessex Water on their Dynamics 365 implementation, there were dozens of processes that could have been custom built from scratch. But most of them were standard business processes that Dynamics handled perfectly well out of the box. The custom development effort went into the things that were genuinely unique to how Wessex Water operated. That is the right approach.
When buying is the smart move
Buying off the shelf software makes sense in most situations, and I say that as someone who makes a living building custom software. Here is when I would almost always recommend buying.
First, when the problem is well understood and widely shared. Payroll, email, project management, CRM, invoicing. Thousands of companies have the same problem, and there are mature, tested products that solve it. You are not going to build a better email system than Microsoft. Do not try.
Second, when speed matters more than perfection. If you need something working next week, you cannot build it. Off the shelf software is already built, already tested and already being used by other people. You can be up and running in days rather than months.
Third, when ongoing maintenance is not something you want to deal with. Custom software needs maintaining. Bugs need fixing, security patches need applying, features need updating. When you buy software, someone else handles all of that. With Crocodile and CampSuite, my team handles all the maintenance, updates and infrastructure so our customers do not have to think about it. That is the whole point of SaaS.
Fourth, when the cost of building is wildly disproportionate to the problem. I have seen companies spend six figures building custom internal tools that could have been replaced by a fifty quid a month subscription. That is not smart. That is ego driven development.
When building makes sense
There are genuinely good reasons to build custom software, but they are more specific than most people think.
The strongest reason is when your business process is genuinely unique and that uniqueness is what makes you competitive. At Gridserve, the way they manage their electric vehicle charging infrastructure is not a standard business process. There is no off the shelf product that does exactly what they need. Custom development was the right call because the software directly supports their core business model.
Another good reason is integration complexity. When you need five or six different systems to talk to each other in a very specific way, and no existing product handles those integrations properly, building a custom integration layer or a custom application that sits on top of your existing systems can make a lot of sense.
Building also makes sense when you are creating a product. RealCube was built from scratch because it was the product. We were not building software to support another business. The software was the business. Same with Crocodile and CampSuite. If your software is your competitive advantage and your revenue stream, building is not just sensible, it is essential.
Finally, building can make sense when you have hit the limits of an off the shelf product and the workarounds are costing you more than a custom solution would. I have seen this a lot with companies that have outgrown their CRM or their project management tool and are spending more time fighting the software than using it.
The questions you should actually ask
Before you make the decision, work through these questions honestly. Not with your ego, not with your gut feeling, but with actual data.
What is the total cost of building, including ongoing maintenance, over three years? Most people massively underestimate this. A custom application is not just the development cost. It is hosting, security, maintenance, bug fixes, feature updates and the opportunity cost of your development team working on this instead of something else. Multiply whatever number you have in your head by at least two.
What is the total cost of buying over three years? Include licence fees, implementation costs, customisation, training and the productivity cost of your team adapting to software that does not fit your process perfectly. This number is usually more predictable, but it is rarely as simple as the monthly subscription fee.
How fast do you need it? If the answer is quickly, buying wins almost every time. Custom development takes months. Good custom development takes even longer.
Do you have the technical capability to maintain custom software? If you do not have developers in house and you are not planning to hire any, building custom software means you are permanently dependent on an external agency. That is not necessarily a problem, but it is a cost and a risk you need to factor in.
Is this a core part of your business or a supporting function? Go back to the first question. If it is core, consider building. If it is supporting, buy.
The middle ground most people miss
Here is the thing that a lot of the build vs buy articles miss. It is rarely a binary choice. The best outcomes I have seen are usually a combination of buying a solid platform and building custom extensions on top of it.
This is essentially what Dynamics 365 is designed for. You get a robust, enterprise grade platform out of the box, and then you build custom plugins, workflows and integrations on top of it to handle the things that are specific to your business. You are not starting from zero, but you are not constrained by someone else's idea of how your business should work either.
At Park Holidays, we took exactly this approach. The core platform handled the standard stuff. The custom development focused on the things that made Park Holidays different from every other holiday park operator. That is the sweet spot.
With Power Platform and Power Apps, this middle ground has become even more accessible. You can build custom applications on top of the Microsoft ecosystem without needing a team of senior developers. It is not right for everything, but for internal tools, workflows and simple applications, it is remarkably effective.
My honest advice
If you are a business owner trying to make this decision, here is what I would tell you over a coffee. Default to buying. Seriously. Unless you have a very clear, specific reason to build, buy something that already exists and get on with running your business.
If you do decide to build, invest properly. Cheap custom development is the most expensive mistake you can make. Hire good people, budget realistically and plan for ongoing maintenance from day one. The initial build is maybe forty percent of the total lifetime cost. The other sixty percent is keeping it running, updated and secure.
And if you are not sure? Talk to someone who has done both. Not a sales person from a software vendor, and not a development agency that only makes money if you build. Find someone who understands your business and can give you an honest assessment. That is literally what I do as a fractional CTO, and more often than not, the answer saves people a lot of money and a lot of headaches.
The best technology decision is the one that solves your actual problem without creating three new ones. Whether you build or buy, keep that as your north star and you will not go far wrong.
