A 301 redirect denotes a permanent, automatic move of a page from one URL to another so that when visitors or bots hit the original URL they are taken to the new one.
Redirects are used for a number of reasons such as:
● The removal of a page
● Moving a site to a new domain
● Merging websites
● Changing a Content Management System (CMS)
● Changing a URL structure
● Eliminating a recurrence of duplicate content
● Replacing old content
Not implementing a 301 redirect correctly when a resource is no longer available at a URL can cause problems. If it is redirected to a missing or dead page, it can return a 404 error, indicating that the page is not available. Redirecting an old URL to the wrong new URL can also result in users reaching content they did not expect. Both of these are harmful to the user experience, and increase the likelihood that the user will leave the site.
Redirection can also allow for the majority of link equity (the impact of links on a page’s search engine ranking) to be transferred to the new URL. This is beneficial if you want to retain the impact of links generated to your old URL.
One disadvantage of redirects is the risk of redirect chains. Redirect chains often happen when the preferred URL repeatedly changes over time. So the initial redirect moved the user from page A to page B. Then eventually page B was redirected to page C, and so on.
These chains may not be obvious to a user, but it can slow page load times and waste the crawl budget of search engine bots. Rather than going from page A to B to C, the redirect should redirect page A straight to page C.
The number of 301 redirects can build up over time and lead to a chain, so this needs to be dealt with as part of routine on-site maintenance.
Once a 301 redirect is put in place, it can take search engines time to discover it. Once discovered the new page will appear in search engines, and the old page will disappear.