301 Redirects are the correct way to permanently redirect one URL to another. The message is sent to both user clients and search engines that follow and process the Redirect and then transfers the link’s value from the previous URL. But how long should you leave a Redirect up before deleting it?
There is plenty of debate about the answer to this question. One of the reasons for this is that Google has provided very little information on the subject and has only rarely spoken out about it. Statements are alternately about individual Redirects and Redirects of entire websites which has therefore led to a great deal of confusion about what is known about the subject, and even people who have years of experience with SEO disagree about how long a Redirect should be left up.
Most developers use a time stamp to show when a Redirect can be deleted. This limit is often set to 6 or 12 months, but the premise of this rule is that both internal links and external links have been aligned which is an essential element that is completely overlooked by many. This leads to lost visibility and a non-optimal use of the opportunities that you have as a website owner.
I would argue that a 301 Redirect should stay up indefinitely as long as internal or external links point to the page that has been redirected. This article presents my arguments in this regard on the basis of the few quotes on the matter and my own experience with link redirection.
So why do developers want to delete 301 Redirects?
Redirects slow down the load speed of every page. Each user agent that reaches a page results in the reloading of all redirects, so if there are a lot of them on a page with many users, this will have a distinct effect on the server’s ability to respond. Therefore they want to delete older Redirects on an ongoing basis.
Adding several thousand individual rewrites will put a lot of load on a server whereas just one or a few general rewrite rules will have less of an impact on the system. It is therefore completely essential that rewrites are done intelligently and use rewrite rules.
Google’s official statements
As mentioned previously, Google has given very little information about how long a Redirect should stay up. At the same time statements are both vague and inadequate.
They also alternate between being about moving whole domains and the redirection of individual pages. These statements get confused and lead to a number of different theories and opinions on the subject, especially when this knowledge is passed on by word of mouth.
The following quotes are all that Google has had to say in specific terms about the lifetime of 301 Redirects.
Theoretically, a 301 redirect is a permanent redirect, so theoretically you can keep that forever. Practically, that’s probably not that reasonable, that you can keep something like that forever… In practice, if we recognize this is a permanent redirect, we try to keep that in mind for the future as well. So if you’ve moved your site, and we have been able to recognize that your site has moved, which might take maybe a half a year, maybe a year or so, then at some point, you can take that redirect down. The thing to keep in mind there is that if there are still links to the old version of the URL, then chance are, we might show the old URL too, if you remove the 301 redirect. If you do make a site move, then you kind of have to follow the guide we set up, which also includes kinda of reaching out to make sure everyone is updating their links to the new version so that these old links don’t end up getting lost.John Mueller, Google (2015)
And if you notice after a year there’s still a lot of normal people being redirected, maybe you can figure out how they are reaching the old domain, is it like an important link you forgot to get updated on the web, is it just lots of people with bookmarks and you can’t really fix their own bookmarks, that’s kind of what I would aim for there, at least a year. John Mueller, Google (2016)
Google’s official guidelines
Immediately after the website move has begun, you should try to update as many incoming links as possible. External links: Try to contact the websites in the saved list of sites that link to your current content and ask them to update their links to your new website.Google official guidelines
Matt Cutts (2011): https://www.youtube.com/watch?v=r1lVPrYoBkA
My interpretation of Google’s statements
My interpretation of these statements is that Google recognises that it may be problematic in practical terms to keep Redirects up forever, but between the lines Google is also suggesting that it might be a good idea to leave them up.
Google, here personified by John Mueller, also recognises only that they are trying to remember the new addresses. They do not promise this and are unable to guarantee it 100%. If there are internal or external links to a URL that are crawled by Google, the page will be indexed once again.
It is strongly implied in both John Mueller’s statement and the quotation from the official guidelines that it is important that you ensure that all webmasters update their links to your website to point to the new URLs so that the old links are not wasted.
However, this is easier said than done and if it involves a large number of external links, it is doubtful you can get all webmasters to update their links. If getting all your external links is not possible, you should keep your 301 Redirects up.
Pages with external links
If external links point into the pages where the Redirect before was previously set up, users who click in via these external links will encounter an error page. This is not a good user experience.
The same happens when the Googlebot crawls the linking external website. Googlebot finds and follows the link and now encounters an error page. Google then re-indexes the error page because there is an external link that points to it and upvotes the relevant URL.
This also means that the link value that was brought from the external link now belongs to the error page which is of course unable to use this value for anything whatsoever. Conversely, we instead want to bring this value to a page that needs external link value which is effectively all active pages on your website.
As previously mentioned, Google actually recommends that you contact webmasters who have linked to your website and ask them to update the link so that it matches the new URL.
Also remember to update internal links
After redirection to new addresses it is absolutely essential that your internal links are updated to point to the final destination rather than the old address which is now being redirected. If you do not update these internal links, it will take longer for the user to reach his or her destination by clicking on the link.
It also creates error pages as soon as you delete the Redirect. Internal link value is wasted on pages that no longer exist and that require no allocation of this value.
Internal links can be updated as soon as the Googlebot has detected and indexed the new address. You can in principle do this right away, but by waiting you will ensure that Googlebot is able to catch 301 Redirects more quickly.
There is a big difference between a complete migration to a new domain and individual Redirects
If you are moving an entire website to a new domain and thus rewriting all URLs, it is important that you allow your Redirects to remain on the old domain for a long period of time.
Redirects are updated on a page-by-page basis, and plenty of time can elapse from registration of the first address until the final address on the website is registered. This all depends on how often and how deeply Googlebot crawls your website.
In other words, between 2 and 12 months can pass before the entire address structure is updated in the Google index.
Redirects from one domain to a new one only put load on the new server if you move the old installation to the new server. If you leave the old installation on a previous server, there is no reason to remove the Redirects at any time. The expense of maintaining a domain and webhotel is minor, and the cost of losing helpful external links can be far higher.
Which Redirects can be deleted and which can be retained?
The following rules explain, using different types of scenarios, when you can delete 301 Redirects. Common to all types of Redirects is the importance of considering the specific scenario instead of using general rules.
301 Redirects of pages with internal links
- After the internal address Redirect is set up, you should update internal links to point to the absolute and final destination rather than linking to the old address.
301 Redirects of pages with external links
- Get webmasters to update all external links that point to the URLs that you have redirected.
- If you are unable to get all links updated and these links are of high or even partially high quality, you should leave the 301 Redirect up indefinitely or until the links to the page disappear for other reasons.
301 Redirect of a complete domain
- Keep the domain and hosting running if there are good external links pointing to your old domain that you cannot get updated.
- Never delete Redirects. There is no good reason to delete them. It will not affect users of your current website as the Redirects are on the old domain and server.
- If you were able to have all external links updated or you have none, you can remove the Redirects and drop the domain on the day that all URLs are updated in Google’s index and now point to the new domain. You can check this using the command site:gammeltdomaene.dk
- If you move files etc. from the old server to the new one, you should update external and internal links and get the new website indexed before deleting the Redirects.
Don’t configure 301 Redirects just for the sake of Google.
Finally, bear in mind that Google is not the only search engine and that links from social media etc. do not crawl and update their own links. If you have a lot of links from bookmark pages, social media etc., this traffic will also be lost once you delete the Redirect. This is why it is important, also with regard to extending the lifetime of your content, that your Redirects are correctly configured.