Managing side effects and lifecycle operations is crucial for data fetching, subscriptions, and DOM manipulation in React functional components. As the creator of CoreUI, a widely used open-source UI library, I’ve implemented useEffect in thousands of React components for API calls, event listeners, and cleanup operations in enterprise dashboards. From my expertise, the most effective approach is to use the useEffect hook with proper dependency arrays. This method provides precise control over when effects run and ensures optimal performance by preventing unnecessary re-executions.