To be effective with agile software development, you need to have solid technical practices. But many organizations are still only implementing process changes to their software delivery cycles. Rachel and Martin discuss why you need technical practices like testing, refactoring, continuous delivery and evolutionary architecture. They cover a brief history of these practices and explain how, without them, you end up with "ball of mud architectures" that slow you down no matter what process changes you make. Viewers will enjoy the contrast in perspectives between Rachel's up to date reality of working on projects with Martin's fading memories of past glories.