The build-vs-buy decision gets treated as a philosophical stance when it's really a practical one — it depends entirely on how close the off-the-shelf option gets to what your business actually needs.
When off-the-shelf wins
If a mature product already solves your problem and your workflow can flex to match it, buying is almost always faster and cheaper. Payroll, basic CRM, and standard accounting are rarely worth building from scratch.
When custom wins
Custom software earns its cost when your workflow IS the advantage — when bending your process to fit someone else's software would mean giving up the thing that makes your business work differently from competitors.
“Buy what's common to every business in your category. Build what makes yours different.”
A quick way to test which side you're on
Ask whether the process you're trying to support is something you'd want a competitor to copy exactly. If yes, it's probably worth building. If it's a solved, boring problem, buy it and move on.
Most businesses end up with a mix — bought software for the commodity parts, custom software for the parts that actually differentiate them.