It hurts in that the tests add inertia to your codebase. Radical changes may require you to cut out portions of tests, for better or worse.
It helps in that, by writing tests first, your code is more testable. And thus less tightly coupled to the rest of your code and easier to change without trashing the whole system. This is the real reason to do TDD: it forces you into doing good design. This is less painful than you might expect in languages that are not Java.
It hurts in that the tests add inertia to your codebase. Radical changes may require you to cut out portions of tests, for better or worse.
It helps in that, by writing tests first, your code is more testable. And thus less tightly coupled to the rest of your code and easier to change without trashing the whole system. This is the real reason to do TDD: it forces you into doing good design. This is less painful than you might expect in languages that are not Java.