Test early, test often- good principle of User Testing

Do it early and often. Usability and visual design helps shape the product’s story. Testing at different stages helps us refine the story by uncovering user motivations, behaviors, as well as validating the assumptions we make during the creation process.
User testing doesn’t have to be lengthy, complicated or formal. The important thing to remember is to stop, validate and refine. When we were testing the Nokia Life app at the initial stage, we performed a lot of informal testing by asking family, friends, colleagues to perform specific tasks for key scenarios. From signing up and requesting a content, we were able to surface user motivations and behaviors by asking them to talk through what they saw and expected as they navigated through the experience.