[wpietri]

I've used TDD both at my paying job and as part of some kinds of exploration. I agree it's more challenging in both places.

The place where I won't use it is when I'm writing throwaway code. If I'm really being exploratory, then I just go write garbage. And when I've done enough exploration to start writing real production code, I'll start fresh with TDD.

I've tried it the other way, where I retrofit tests to existing experimental code. But because the experimental code was to help me learn something, it generally ends up being poorly designed. It's only once I understand the big picture that I know the write way to express my understanding in code. At first I didn't like throwing out the experimental code, but now I prefer it in that it frees me to be entirely experimental, rather than writing something that's half experiment, half production grade.