A 301 redirect is a directive that website developers use to permanently redirect visitors from one URL to another. These maintain the connections between historic URLs and current URLs so that, as websites evolve, the connections between individual URLs can be maintained through site changes. These become a critical element in maintaining rankings and providing good information to the search engines in regard to what old pages relate to the new pages.
Additionally, besides the intrinsic value for search engines, it also provides benefit to website users by making it easier for them to get to the newest version of information provided by your website. This means that the user will not receive a ‘Page not Found’ error and provide an overall better repeat experience for a user.