working on systems that don&#x27;t have automated tests, and are designed such that adding automated tests is not easy.<p>you don&#x27;t have to practice TDD, but it is a fantastic idea to add automated tests early on when the architecture of your system is still fresh and changeable.<p>projects that don&#x27;t consider &quot;testability&quot; as a requirement tend to produce system architectures that are not testable.