<i>I&#x27;ve never written unit tests in my life, and my code works most of the time.</i><p>How do you know?<p>I agree with your point about taking more time to think about the way your code works, to design data structures, to use rigorous methods to make sure the code works, but ultimately you still have to check things. If you haven&#x27;t automated those checks then either you&#x27;re checking things manually or you&#x27;re not checking them. On any significant project there&#x27;s too much code to check manually.