useState vs useReducer: Choosing State Tools by Criteria, Not Habit

The article argues that the common rule of thumb, using useState for simple state and useReducer for complex state, is incomplete. It contends that state complexity depends on ownership, how updates occur, the business rules and invariants governing them, and how long the state persists. The author proposes a set of five evaluation dimensions to guide the decision before a tool is selected. Using examples such as a checkout flow, a simple toggle, and a payment workflow with explicit transitions, the piece illustrates that the number of state variables alone is not a reliable criterion. The central takeaway is that the problem should shape the tool choice, not the reverse.