Though usually the same thing in practice, a test first environment is not conceptually the same thing as Test driven development. The reward cycle of TDD and

Though usually the same thing in practice, a test first environment is not conceptually the same thing as Test driven development. The reward cycle of TDD and the focus that TDD brings to writing code are the reasons I use TDD. The added confidence in correct code is also extremely helpful. As I see it, if one were "in the zone" from 8-5 for a week, and had a clearly defined and understood spec, most software wouldn't take more than a few weeks to build. Since being "in the zone" and understanding a well-defined spec aren't really that easy. Most time spent (in my experience) is understanding the spec and wrapping your head around the problem. This is a reason why pair programming can be so helpful. Regression testing aside, writing tests is valuable to me mostly because it helps to define the problem for me enabling me to more quickly write code.