Google’s Policy on Redirects Confirmed

A long time ago, Google advised all webmasters to keep redirects online for a minimum of one year. This week, Google’s Gary Illyes took to Twitter to provide what he called a “concrete answer” to a long-standing debate.
Having researched the way Google Search handles redirects internally, he revealed that indeed the minimum time redirects should be kept up is “at least one year.”
At which point, Google passed all signals from the origin URL to the destination URL; from the time the redirect was found by Google to the time the removal of the redirect was detected.
This means all signals passed to the destination URL from the origin URL will permanently be associated with the destination URL, even when the redirect has been removed. When the redirect is removed, all signals going forward will not be associated with the destination URL, but the origin URL.
Clarifying the Confusion
The full statement published on Twitter by Gary Illyes reads as follows:
“Hands up if you asked us recently for how long you should keep redirects in place! I have a concrete answer now: at least 1 year” Immediately, conversation was sparked between webmasters and SEOs as to what all of the above really means. Illyes admitted a little later he may have sparked confusion, after SEO Patrick Stox said:
“So the main thread branched a lot with a lot of questions but I think this is the main takeaway. 301 redirects really do consolidate those signals (usually in under a year since G first crawled) and those signals still stay with the new page even after a redirect is removed.”
While the advice from Google is to therefore keep redirects live for at least a year, most SEOs continue to advise keeping them up for the longest time possible for the benefit of their target audience.
Why it Matters
While the above technically represents no more than confirmation of what many already suspected, it is the first time Google has confirmed the permanent passing of signals to the destination URL, even following the removal of the redirect.
That is, just as long as the redirect has been up for at least a year.
In SEO terms, this means that online businesses and webmasters can now confidently remove redirects that have been live for at least a year.