Your software shouldn't depend on a monthly payment nobody mentioned

There's a real, documented case of a founder who, after comparing providers, choosing one at a mid-range price, and signing a contract with clear stages, reached the third stage of the project and got news he wasn't expecting: some of the agreed-upon features, not add-ons, couldn't be built the way they'd been planned.

The alternative he was offered was to pay 20% of the total project cost, every month, to rent an external service his own application would depend on to function. His savings were already committed to the project. The provider's response, according to his account, was to wait until he had the money.

This isn't a case of bad luck with one specific provider. It's what happens when software gets built depending on external pieces (a third-party API, a service with a recurring cost, a licensed library) without that dependency and its real future cost being discussed before signing. The initial budget covers building the software. Nobody mentioned that it would also need ongoing payments just to keep working.

Before approving a build, it's worth asking explicitly: what external services does this depend on to function, and what's the real recurring cost of each one, beyond the build cost? It's the same logic as calculating total cost over 3-5 years instead of looking only at the initial quote, applied to a very specific case: an external dependency nobody put on the table in time.

Well-planned software documents those dependencies from the start, with their cost, so the decision to use them, or avoid them, is yours and informed before signing, instead of a surprise in the project's third stage.