TDD Is a Tool, Not a Religion

In my experienced years of development: - with TDD

- implementation first and then tests

- just implementation without test,

I recently came to the following conclusion:

If you perform TDD, your specification that you try to implement are the business requirements / the goals you like to achieve.

If you don't perform TDD, your specification becomes the algorithm/thing itself you are developing and a (potentially fuzzy) idea in your head.