"How should you interview your customers?"

A. Only when you want to learn how people have a meeting! For designing products and systems you first need to understand how your users work, then support that work in your design. But people can't articulate how they really do their work, so you have to get out of the conference room and go to their workspace to see them do it. This is the essence of Contextual Inquiry. See how Contextual Inquiry differs from other techniques.

A. Only for as long as it takes to get the names of the people who do the actual work. These are the people you need to interview. The manager may have an idea of how the work is done at some high level, but you can be sure the actual workers do it differently to deal with real-world problems and the inevitable work-arounds. Using Contextual Design, you move from relying on abstractions and pure intuition to using real work practice data. Only then will you see a clear path to the best design for your users.

A. Nothing. You're observing and discussing with the user, actively learning and documenting how they perform their work as they do specific tasks. You're like an apprentice, asking why they did what they did so you understand their motivation and intent. This is how you begin to understand user needs. Learn about the importance of both capturing and interpreting. Read tips on Contextual Inquiry.

A. That's right, no guided questions. You're there to have users show you how they work, so let them. Rather than asking hundreds or thousands of users a set of canned questions, you go deep to understand the actual work structure with a much smaller and carefully selected group of users. With Contextual Design you usually only have to interview 15-30 people to capture requirements, even for an entire market.