React Performance Problems Usually Start with State, Not Rendering

Source: Dev.to

Why State Design Is the Root of Performance Issues

When a React application starts to feel slow, the instinctive response is often to reach for optimization tools—memoization, useCallback, useMemo, and profiling sessions. While these tools are valuable, they’re rarely where the real problem begins. Most React performance issues originate in state design, not rendering itself.

React is extremely good at re‑rendering; rendering is cheap. What becomes expensive is what triggers re‑renders and how much of the tree is affected. When state is lifted too high, tightly coupled, or mutated indirectly, small changes can ripple through large portions of the application.

Common Smells

Global or Top‑Level State

A frequent symptom is global or top‑level state that changes frequently. When many components depend on the same piece of state, React is forced to re‑evaluate large subtrees even if most of them don’t truly care about the change. The result feels like a rendering problem, but it’s really a data ownership problem.

Premature Optimization

Adding memoization too early often increases complexity without solving the root cause. It introduces dependency management, stale values, and mental overhead—all to compensate for unclear state boundaries.

Best Practices for State Ownership

• Keep state close to where it’s used. State should live as near as possible to the components that read or write it.
• Derive data locally instead of storing it globally. Compute derived values inside the component that needs them.
• Allow free re‑renders. When components have isolated, cheap renders, the cost of re‑rendering is negligible.

A Helpful Mental Shift

Instead of asking, “How do I prevent this component from re‑rendering?” ask, “Why does this state change affect so much of the app?” The answer usually points directly to the fix: refactor the state so that only the components that truly need it are subscribed to its changes.

Architectural Focus

React performance is largely an architectural concern. Get state ownership and data flow right, and rendering tends to take care of itself.