This article by Sam Moore discusses the intricacies of a redesign, and the do’s and dont’s, including best practices.
In certain situations sites that have grown truly dated sometimes need a more intense, focused design effort to move away from the pattern of periodic redesigns. The best strategy in a case like this is to make this work gradual and incremental, minimizing risk and reducing costs over time. This approach helps users orient and recalibrate their mental model of your site with minimal frustration. Instead of simply flipping the switch all at once, use tactics like canary releases and feature flags to help validate changes with select user groups before rolling them out to the full user base.