Once you see that an answer is not serving its question properly anymore, it should be tossed away. It's just their natural life cycle.
They usually kick and scream, raising one hell of a ruckus when we ask them to leave. Especially when they have been with us for a long time.
You see, too many actions have been based on those answers. Too much work and energy invested on them. They feel so important, so full of themselves. They will answer to no one. Not even to their initial question!
The hardest thing about customer interviews is knowing where to dig. An effective interview is more like a friendly interrogation. We don’t want to learn what customers think about the product, or what they like or dislike — we want to know what happened and how they chose... To get those answers we can’t just ask surface questions, we have to keep digging back behind the answers to find out what really happened.
Start all of the pieces of work a little bit earlier. The key to starting work early is not succumbing to the pressure of having to finish the work. Don’t worry about finishing. If you’re a developer, you can start doing things while your design or information architect are working because a lot of your work actually isn’t dependent on their work. Some of it is, so you probably won’t be able to finish, but that shouldn’t stop you from starting.
Share Work-in-Progress Early and Often
When you share work-in-progress, share it with the caveat that no feedback is needed at this point. You’re simply sharing it to let people know where you are. For example, if you have to make 12 wireframes, share it when you finish 2 or 3. Rather than spending a whole week to drop 12 wireframes, share 2 – 3 wireframes every 2 days. The more often you do this, you start to build rhythm, and rhythm builds momentum.