Original FTW field note
A prototype is a question.
Build just enough to learn whether an idea deserves the next investment.
Ask one useful question
Can this workflow save a person time? Can a customer understand this new experience? Give the prototype a specific question to answer.
Put it in real hands
Use representative work and real feedback. A polished demo is useful when it helps you see what a person actually needs.
Choose what happens next
Keep the useful part, change what gets in the way, or stop. The value of a prototype is a clearer next decision.