Choose the right level of fidelity
Wireframes focus on structure, mockups explore visual decisions and interactive prototypes connect screens into journeys. A polished prototype does not prove that the backend or an integration works. Use a technical experiment separately when the uncertainty concerns device capabilities, data or performance.
Test representative tasks
Ask intended users to complete specific actions without coaching them through the interface. Observe where they hesitate, misunderstand information or take a wrong path. Include error and empty states where they affect the journey. Keep the test focused on the questions you need to answer rather than collecting opinions about appearance alone.
Turn findings into delivery decisions
Prioritise the issues that prevent users from completing the core task. Update the brief and acceptance criteria before implementation. Keep the design assets and decisions organised for handover. Prototyping can reduce avoidable rework, but it remains a design and learning tool rather than a guarantee that the final product will succeed.