If you have a redirect live for a year, you can then remove the redirect and Google will continue to pass the signals from the origin URL to the destination URL.
That means, the signals passed from the origin URL to the destination URL will always be associated with the destination URL, even after you remove the redirect. But after you do remove the redirect, the signals going forward will then be associated with the origin URL and not the destination URL.
Got that?
The announcement. Here is Gary’s announcement on Twitter on this:
What about the signals passing? So Gary Illyes and a bunch of SEOs went back and forth trying to clarify what this means. I summed it up above but here is Patrick Stox, a long time SEO, summing up Gary Illyes’ clarification:
More caveats. Technically, it can be less than a year, but to be safe, keep it up for a year to be safe that the signals will stick with the destination URL.
Also for users, you probably want to keep the redirect up for as long as possible. But that is up to you.
A final point, which I mentioned above, is that the clock starts ticking when Google first discovers the redirect. So if you are tracking it that closely, it is based on the time Google crawled the redirect, not when you actually put up the redirect.
Why we care. This is the first time Google has officially confirmed that the signals passed through redirects last forever even after a redirect is moved, if the redirect is live for over a year.
So now if you have clients that really want to remove redirects for whatever reason, if the redirect is live for a year or more, it is safe to do so from an SEO perspective specific to Google Search.
More importantly, if the redirect is removed over time because of just normal maintenance and it has been a year, you still do not need to worry.