Keep old redirects live far longer than you think, often a year or more, and effectively indefinitely while valuable inbound links still point at the old URLs. This is a long working window, not a short deadline. A 301 redirect has to stay up long enough for Google to fully process it and move the old URL’s signals to the new one, and that processing is slow and uneven across a site. Beyond Google, real users and other sites keep hitting the old addresses through bookmarks, links, and references, so the redirect is still doing live work long after you might assume it is finished. Plan for patience, not a quick cleanup.
The reason a year is a floor rather than a generous estimate is that signal transfer and traffic migration both lag. Google may take many months to reprocess every redirected URL and settle the new pages, and during that time removing a redirect risks dropping the old URL’s accumulated value instead of carrying it forward. The safe posture is to leave the redirects in place well past the point where rankings look stable, because “looks stable” and “fully processed across the whole site” are not the same thing.
The link-dependent case pushes the window further still. As long as valuable inbound links continue to point at an old URL, the redirect is the only thing capturing that link equity and sending those visitors to the right place. Those external links are outside your control and may persist for years, so for any old URL with meaningful links still aimed at it, the redirect should be treated as effectively permanent. Removing it would waste links you cannot get rebuilt.
To apply this, do not set a calendar reminder to tear down redirects after a few months. Keep them live as long as links and traffic still hit the old URLs, and check your logs and referral data before retiring any of them. Retire a redirect only once an old URL has stopped receiving meaningful traffic and no longer has valuable links pointing at it, and leave the rest in place. Lean long, and let the data, not a deadline, tell you when a redirect has finished its job.