Explore the principles of good software design and how to avoid over-engineering in this 20-minute conference talk by Dave Farley, author of "Continuous Delivery" and "Modern Software Engineering." Learn about the Extreme Programming concept of YAGNI (You Ain't Gonna Need It) and the evolutionary design approach known as "design through refactoring." Discover strategies for managing complexity in software systems while maintaining flexibility for future changes. Gain insights on striking the right balance between adaptability and avoiding the pitfalls of big ball of mud legacy systems. Delve into practical techniques for adopting an evolutionary approach to design that allows for continuous improvement as understanding of the system grows.