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 want you to consider instead the possibility that Waterfall came to exist, and continues to exist, for the convenience of managers: people whose methods are inherited from military and civil engineering, and who, more than anything else, need you to promise them something specific, and then deliver exactly what you promised them, when you promised you’d deliver it. There exists many a corner office whose occupant, if forced to choose, will take an absence of surprises over a substantive outcome.
Features don’t work, in the sense that they can be easily gamed. A brittle and perfunctory implementation, done quickly, is going to score more intramural brownie points over a robust and complete one. If the question is "does product A have feature X?" then the answer is yes either way.
We use the term feature factory as a pejorative to designate companies addicted to adding features, while accumulating incalculable so-called technical debt. This situation is driven by management for the convenience of marketing, and I am skeptical that a more faithful application of Agile principles will correct it. Indeed, I suspect Agile processes are constitutionally vulnerable to this kind of compromise.
The presence of a feature can only indicate to a user if a goal is possible, behavior will determine how painful it will be to achieve it.