React is fast by default, until it isn't. The good news is that the vast majority of real-world performance issues trace back to a small set of patterns. Fix those, and you rarely need exotic optimizations. Measure before you optimize The first rule of performance work is to never guess. Use the React Profiler and the browser's performance panel to find what actually renders, and how often. Premature optimization Wrapping every component in memo and every value in ...