We earn our money building custom software. Even so, our first recommendation in initial calls is surprisingly often: buy it off the shelf. For accounting, email, payroll, or textbook project management, there are mature products whose value no custom build can match. So the question is not which approach is better in general. The question is which category your specific process falls into, and there are usable criteria for that.

The default: standard software, no debate

Wherever your process looks like it does at a thousand other companies, the finished product wins. It is available immediately, battle-tested by many customers, continuously developed, and the legally sensitive parts, payroll and accounting above all, are kept up to date by the vendor. A custom-built accounting program would be more expensive, worse, and a maintenance liability.

As a rule of thumb: the closer a process sits to legal requirements or industry standards, the stronger the case for standard software. Custom becomes interesting where your workflow is a competitive advantage, or simply a quirk no vendor covers.

The 80 percent problem

The most common grey zone looks like this: a standard tool fits 80 percent. But the missing 20 percent happens to be your daily business, the pricing logic, the particular order handling, the step that only exists at your company. Then the workarounds begin: required fields filled with placeholders, note fields carrying structured data, and next to the tool an Excel file grows again to catch what the tool cannot.

In this situation you pay twice, license plus manual labour, and still do not have a clean process. Whether a custom tool pays off then depends on how expensive those 20 percent are in daily life: how many hours a week the detours cost, how often they produce errors, how many people are affected. Put that calculation together before talking to any vendor, including us.

Run both sides over five years

Bought software feels cheap because it bills monthly; custom software feels expensive because the price arrives all at once. They only become comparable over a longer horizon; we recommend five years:

Cost item	Standard software	Custom development
Purchase	none, the subscription starts right away	one-off development cost
Running costs	per-seat license × team size × 60 months	hosting and operations
Maintenance	included in the subscription	roughly 10 to 20 percent of the build cost per year
Add-on features	paid modules	extensions billed by effort
Hidden item	recurring hours spent on workarounds	refinement during the first months
Switching later	data export, new habits	depends on code ownership and documentation

What the custom side tends to keep quiet about

The five-year comparison favours custom development more often than people assume, especially beyond ten or fifteen users. Nor is building an exotic path: a representative Bitkom survey (2017) of 503 companies found that one in three companies in Germany develops its own software, and among businesses with 500 or more employees the share was 64 percent. But there are real drawbacks a serious proposal has to name. A custom tool is worse than the standard product on day one: fewer features, no years of accumulated bug fixes, no community with how-to guides. It becomes good through use and refinement.

And it makes you dependent on a vendor if you are not careful. Before signing, settle who owns the code, whether it is handed over with documentation, and whether another team could take it on. We call that the exit strategy and it is written into every proposal we make; where a vendor dodges the topic, we would not sign ourselves.

The overlooked middle path: standard at the core, build small at the edges

The decision is rarely all or nothing. Often the best architecture is: standard software for the standard parts, accounting stays accounting, plus a small custom tool exactly for the 20 percent that fits nowhere, connected to the existing systems.

A practical example of the kind we often encounter: a trades business keeps its accounting package and payroll, but gets its own job planning tool with time tracking on the phone, because precisely that part matched its workflows in no standard product. The custom tool stays small and therefore affordable, while the mature products keep doing what they are good at.

The short version as a checklist

If you take one thing from this article, make it this order of checks:

Is there a standard product that fits more than 90 percent? Buy it, done.
Does it fit 80 percent and the gap is cheap to live with? Buy it and accept the workarounds, deliberately.
Does it fit 80 percent and the gap noticeably costs hours, errors, or nerves? Run the five-year numbers and consider the middle path.
Is the process a genuine quirk or a competitive advantage? Then it is a candidate for a custom tool, starting with the most painful part, not the grand platform.