Is it good to test about 5 users on an interface design?
The best results come from testing no more than 5 users and running as many small tests as you can afford. The most striking truth of the curve is that zero users give zero insights.
Why is user research design important?
User research provides an essential foundation for design strategy. It helps you to create an optimal product for users. Most importantly, you'll have the data to back your strategy and design decisions. User research also helps you to identify early adopters who would use your product.