In the requirements phase, you defined a clear set of key use cases. Keep these priorities in mind and avoid adding edge cases to this list. As you get into the details of the design, new scenarios will come up that you hadn’t considered. Before expanding the scope of the design to handle these new scenarios, carefully consider the impact.
The long tail
Key use cases
These are the most important and most common conversational paths that users will take through your feature. Focus the majority of your effort on making these paths a great user experience.
These are less common, and often less direct or less successful, conversational paths through your feature. Take the time to adequately support them, but avoid spending too much time and effort designing them.
These are highly uncommon paths. Consider whether generic prompts like “Sorry I’m not sure how to help” are good enough, or if you can be a little more specific with a similar minimally viable solution.
Use the 80/20 rule, or Pareto Principle, to avoid overdesigning.
For conversation design, this rule is a way of saying that not all paths are created equal. 80% of users follow the most common 20% of possible paths in a dialog. Therefore, invest resources accordingly for the biggest impact.
Similarly, there are trade-offs in terms of perfection or completeness. It may take 80% of the work to really polish the last 20% of the project. In these cases, the unpolished effort may be “good enough”.