Measuring performance metrics in React Native apps can be challenging due to the framework's limitations. However, with custom instrumentation using tools like New Relic, developers can gather valuable insights into their app's speed and responsiveness. The author of this article shares their experience in measuring component load time, user session time, and user interaction in a React Native app using class components and functional components. They provide examples of how to implement performance metrics such as recordBreadcrumb(), capturing class component load time, recording app launch count, calculating user session time, and capturing user interaction in both class and functional components. The article concludes that with forethought and planning, developers can accomplish many basic performance metrics using just the recordBreadcrumb() instrumentation, and provides a unique perspective across their entire system.