The concept of "user-centric perceived performance metrics" has become increasingly important for web development teams to optimize website speed and user experience. New Relic Browser now offers two such metrics, first paint and first contentful paint, which track the amount of time users wait for websites to start rendering or for a "web experience" to begin. These metrics help developers measure and optimize the user experience by answering questions like "How much time passes before users see content?" and "How much time passes before users can interact with elements on the page?" By adding these metrics, web developers can better quantify their end-user experience and more accurately gauge site performance against user engagement and perception.