I&#x27;ve been writing software for decades now, and I find that it&#x27;s quite the opposite. Other than using an SCM, nothing has been as much of a game changer for me as automated test suites.<p>I&#x27;m able to tackle bigger and larger problems with more confidence. I can tell when my new code has caused an error in some dusty corner. I more easily think through edge cases and sad paths. I can show someone my tests and they can understand what the module is supposed to do.<p>For the record, I don&#x27;t TDD&#x2F;BDD much anymore. I <i>do</i> use the lessons I learned while I was to write more testable code.