Search engines continue to keep the original URL in their index for a period of time after a 301 redirect is implemented, regularly checking to ensure that the redirect is still active and functioning correctly. If the 301 redirect is removed or stops working, the new URL can lose the SEO reputation and authority that the original URL had built up over time. This loss can negatively impact your site's search rankings and traffic. For this reason, it is crucial to keep your 301 redirects intact and active for an extended period, typically at least 6 to 12 months. Compared to a 302 redirect, which is temporary, a 301 redirect is far more effective for SEO because it signals a permanent move and transfers ranking signals properly.