As with most software engineering tools and practices, the context matters. I'd imagine that TDD is good when you know exactly what the requirement that the pr

As with most software engineering tools and practices, the context matters. I'd imagine that TDD is good when you know exactly what the requirement that the project has. i.e. TDD is good in the implementation phase but not the design phase. In the design phase, you often don't know exactly what the problem really is, so you need to keep things as loose as possible because you're going to experiment. I imagine that in many small business scenarios these two phases are often fused together, so TDD wouldn't appeal that much for them.