Redesigning a website is usually about making its experience better. But change doesn’t guarantee better, just different. This is why user experience (UX) designers focus so much on user research. The more you know about user needs, as well as business and other requirements, the more you can eliminate some of that uncertainty about the impact of a new design. However, you will never know for sure how a design choice will perform until it's used with real users in real life. This is a nerve-wracking reality. A UX designer nor most project stakeholders are comfortable taking the risk of just changing something and seeing how it goes. Enter A/B testing.