[zabil]

Well, there's time you save on testing.

TDD gives me quick feedback. Its faster to run unit tests vs deploying and testing the functionality. I'd say TDD adds very little or no overhead.

[spronkey]

I would agree most of the time. However in my experience you often end up with at least some small part you have to figure out how to test-drive - i.e. using a dependency. Then you have a choice of "TDD this and write proxies or some other kind of wrapper around everything", or "just go with it".