Console Logging Slowing Down React Render

1. console.log in render function or component body
2. Logging large objects every render
3. Logging complex computations
4. DevTools performance monitor slowing debug
5. React.StrictMode double-rendering during dev

Move logging to effects, not render:

// Bad - logs every render
function Component() {
  console.log('render', data);
  return 
{data}
;
}

// Good - logs only on data change
function Component() {
  useEffect(() => {
    console.log('data changed', data);
  }, [data]);
  return 
{data}
;
}

Use conditional logging or remove in production.