Prototyping's primary value lies in its ability to test and validate design decisions before development. During the early design stages, teams generate numerous ideas and assumptions about user needs and behaviors. Rather than debating these ideas theoretically, prototypes provide a practical way to test them with real users. For example, your team might assume users prefer a tab bar navigation, but testing could reveal they actually find a hamburger menu more intuitive for your specific app.

Prototype testing helps validate multiple aspects of your design: accessibility, interactions, navigation patterns, layout effectiveness, and overall user experience. Modern prototyping tools allow testing across different devices and screen sizes, helping teams understand how their design performs in various contexts. This comprehensive testing approach helps identify potential issues early when they're less expensive to fix and builds confidence in design decisions through actual user validation rather than subjective opinions.