It has pretty much nothing to do with your experience level, your familiarity with the project or the language or tooling. When those things matter, they amplify this phenomenon, but the baseline effect is already high.

It’s a function of requirements being ambiguous by design. Non-engineering stakeholders have a severe need for requirements and specs to be fungible and ambiguous, such that whether or not the state of the project satisfies requirements is fundamentally not codified in any objective document and no test can reflect useful objective measures of it. Tests can only loosely approximate it and the ways to do so are always shifting and changing and up to a subjective interpretation of some non-technical people.

Perhaps the only objective measure that non-tech people will agree to be specific about is financial cost, and even then usually only after it becomes a problem.

That’s every project in a product-oriented tech company period, and anyone claiming otherwise is full of it.

There can be isolated, tiny pockets of maintenance work or last stages dev work once you pass a point of no return when business people can no longer sustainable lobby for requirements to continue to be ambiguous and fungible, and finally you can start proving things with accurately scoped tests, but it’s so late in the game that the idea you could do something like TDD at that point is comical.

Instead, becoming a good product-oriented developer means in part learning how to write well factored tests on the fly at the same time you are writing the code to be tested, and keeping testing code clean and set up with fixtures and set up to run in highly automated ways, so that when you’re inevitably ripping stuff out of the implementation for the 18th time due to yet another priority pivot from sales, you can nimbly also update the tests as you go.