The maintenance cost that arrives later
Software that is quick to build is often expensive to maintain, and the bill lands when the company is busiest.
The cheapest bid almost always wins the tender, and almost always becomes the most expensive one within three years. The difference does not arrive as a single large invoice but as a series of small things: every change needs the same person, every update needs manual testing, and every incident needs guesswork.
What makes a system cheap to maintain is not its programming language but three things you can check before signing: are there automated tests, is there a record of decisions, and can someone else run it on an empty machine within a day.
All three can be demanded as handover conditions. What is rarely done is asking for them at the start, while the price is still negotiable.
