Kano Model
By Noriaki Kano
The Kano Model can be used to help prioritize product features. The model groups features into different categories based on customer preferences and expectations. The categories are generally; Performance, Must Be, Attractive or Indifferent. Must-be features are things the customer has to have in order to use the product. Performance features are generally linear, meaning the more you have of it the happier your customer will be. Attractive or delight features are unexpected features that your customers love.
These categories can be determined for your product by using the Kano questionnaire, which asks the user's how they would feel if they had the feature and how they would feel if they didn't have the feature.