301 Redirect is a permanent redirect that sends users and search engines from an old URL to a new URL.
It matters because development decisions affect speed, security, scalability, tracking, SEO, and maintenance. A site that looks good but is fragile or hard to update can quietly hold back every marketing channel.
Example
Example: During a redesign, /old-seo-services/ might permanently redirect to /seo/. A correct 301 helps users and search engines reach the new page without hitting a dead end.