No Direct useEffect Never call directly. For the rare case of syncing with an external system on mount, use . The only place may appear directly is inside reusable custom hooks (like itself, or a hook when no fetching library is available). Components must never import or call . The 6 Rules Rule 1: Derive state, do not sync it If you can calculate it from existing state/props, compute it inline. For expensive calculations, use : Smell test: You're about to write or state that only mirrors other state/props. Rule 2: Use data-fetching libraries Effect-based fetching creates race conditions and…