Performance-Driven Development (PDD) is a process that empowers developers with the necessary tools to write high-performance code from the outset. It involves setting thresholds for performance and using diagnostic tools, such as debug bars and profilers, to identify areas of improvement. By making performance a first-class consideration in the development cycle, teams can ensure that their applications are optimized for speed and efficiency. The goal is to encourage developers to write clean, efficient code from the start, rather than relying on quick fixes or workarounds. This approach requires leadership buy-in and a commitment to using diagnostic tools as part of the development process. By adopting PDD, teams can deliver high-quality software that meets performance expectations and sets a good example for best practices in PHP development.