As an engineer, one of the most demoralizing questions is "Why has the website gotten slower?" As a business, the direct impact performance has on revenue is well known. Performance is not scalable or sustainable without the tools to benchmark your system. As the owners of their code, the engineers at Wayfair are in the best position to maintain and optimize the application. In this talk we will cover how we used distributed tracing to break down parts of our monolithic codebase as if they were discrete services, allowing us to delegate ownership. We'll also explain how we're monitoring for long term regressions and how this methodology is laying the groundwork for future platforms.