If you're learning React, you've probably heard these terms everywhere: React.memo useMemo useCallback At first, they look confusing. But all three solve one major problem : ⚡ Unnecessary Re-renders & Performance Issues This guide explains: what each one does why they exist how they are connected when to use them interview explanations 🤔 Why Do These Exist? In React, components re-render very frequently. A component re-renders when: state changes props change parent component re-renders Most of the time this is fine. But in large applications: expensive calculations recreated functions unnecessary child renders can slow down the application. That’s why React provides: React.memo useMemo useCallback for optimization. 🧠 First Understand One Important Thing In React: function App () { console .…