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.
I am going to deal with several subjects that, in themselves, are already well recognized as within the province of city planning: subsidized dwellings, traffic, city visual design, analytical methods. These are all matters for which conventional modern planning does have objectives and therefore does possess tactics—so many tactics, so well entrenched, that when their purposes are questioned they are generally justified in terms of the conditions laid down by still other tactics (e.g., We must do this for the purpose of getting the federal loan guarantees). We become the prisoners of our tactics, seldom looking behind them at the strategies.