I'm in a project where scenarios are really different. Should I be designing for the common scenario or the worst case?

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  • I think there is insufficient information to provide a suitable answer to this question. Do you have any information on the distribution of user groups or more information about the product or service you are designing? – Michael Lai Nov 9 at 23:08

You should be designing for everybody. Or at least for as many people as you can.

Designing for edge cases is usually a good idea, because that will usually mean that your target will be broader and that you'll cover users that would usually left out of the equation.

Of course, this is something you'll need to find out by testing. If your edge case covers one user in the world and it takes 100 hours of design and coding maybe is not very wise to design for that user alone.

But in my experience, what looks like an edge case many times is more common than what we thought at first. Not to mention that designing for edge cases sometimes makes "common users" discover and appreciate a feature they wouldn't use otherwise. This is more common in physical UX and complicated GUI, but it could apply to any kind of project

One thing I'm not sure is what do you mean by worst case. In general, I have seen this word is usually related to accessibility, not sure if that's your case. If this is the case, designing with accessibility in mind shouldn't be considered an edge case per se. Furthermore, it's a basic requirement, and really easy to fulfill once you get used to it, it's almost automatic


Do you believe that thinking and brainstorming the extreme edge cases from the beginning will be a real help for your project? If you are addressing every edge case from the beginning, in my personal experience it distracts the team from focusing on defining the right problem and moreover, it misleads to find the right opportunity. Problems definitely come up naturally at different points of the design process and you always have to be ready to face them.

Personally, I would try to understand and finish the happy scenario first because I really want to focus and release my creative energy to find a good momentum.

If 99 percent of the people are using the happy flow use case of the product you are designing and the use case is well understood, you should focus on your main use case, in the beginning.

Thinking of edge case in the beginning generally, complicates the primary path. It is better to approach with a happy flow if the edge cases of your product will not affect the quality and will not danger the existence. If the flow really affects the quality of life, for example, human factor, accessibility, etc. then you cannot ignore them you should make sure the core functionality of your product is accessible to everyone.

But of course, it all depends on projects :)

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