Should you really maintain redirects when migrating to a new domain?

Why does Google insist so much on redirects?

The old domain has accumulated trust signals over time: domain authority, backlink profile, crawl history, behavioral data. Without redirects, Google treats the new site as a completely new entity, ignoring all this history.

301 redirects allow Google to progressively transfer these signals to the new domain. It's an active process of recrawling and re-evaluation, not a simple instant copy-paste.

What actually happens during this transition period?

Google continues to crawl the old domain to detect redirects, then visits the corresponding new URLs. The ranking signals are gradually transferred: first the PageRank transmitted by backlinks, then quality and engagement metrics.

The transfer duration varies depending on the crawl frequency of the old site, the number of URLs involved, and the quality of technical implementation. A small site can stabilize in a few weeks, a large portal in several months.

What are the valuable signals mentioned by Gary Illyes?

• Backlink profile: each link pointing to the old domain must be redirected to the equivalent page on the new site
• Domain authority: the trust accumulated at the domain name level itself
• Crawl history: the frequency and priority that Googlebot assigns to the site
• Behavioral data: user engagement metrics associated with old URLs
• Freshness signals: content update history
• Trust rank: quality and reliability indicators built over time

Is this directive aligned with real-world observations?

Absolutely. Migrations without redirects cause systematic traffic collapses. I've seen sites lose 70-90% of their organic visibility within weeks after simply switching domains.

What's interesting is that Gary Illyes speaks of "a few weeks to a few months" — it's deliberately vague. The reality? For an average site, count on a minimum of 3 months for stabilization, often 6 months for a complete signal transfer. Large sites may require a year.

What nuances should be added to this statement?

Google doesn't specify the duration of maintaining redirects. In theory, they should remain permanent. In practice, many experts recommend a minimum of one year, or even two for high-authority sites.

Another point: Gary Illyes speaks of "valuable signals" but remains vague about their exact nature. It's difficult to objectively measure authority or trust transfer. [To verify] with controlled A/B tests on different types of sites.

In which cases might this rule not apply strictly?

If the old domain has been manually penalized or algorithmically, maintaining redirects can transfer those penalties. In that case, starting fresh might be preferable — but this is a rare and radical scenario.

For a very new site (less than 6 months, few backlinks), the impact is marginal. But even then, better to redirect on principle: you never know which signals Google values behind the scenes.

What do you need to do concretely before a domain migration?

Prepare a complete URL mapping: each old URL must have a destination on the new domain. Prioritize 1:1 redirects (page to page) rather than redirecting everything to the homepage.

Configure 301 redirects at the server level (Apache .htaccess, Nginx, web server). Avoid JavaScript or meta refresh redirects — Google follows them, but it's less reliable and slower.

How do you verify that the migration is going smoothly?

Monitor Search Console: activate the new domain property, declare the address change in the dedicated tool. Monitor the evolution of impressions and clicks week by week.

Verify that redirects work with a crawler (Screaming Frog, Sitebulb). Test a sample of important URLs to confirm they return an HTTP 301 code and point to the correct destination.

What mistakes should you absolutely avoid?

• Never delete the old domain without having set up redirects first
• Don't redirect all pages to the new site's homepage — that's disguised soft 404s
• Avoid redirect chains (A → B → C) — Google may give up after 3-5 hops
• Don't forget to update the XML sitemap with new URLs
• Don't neglect backlinks: contact your main partners so they update their links
• Maintain redirects for several months minimum, ideally a year or more
• Actively monitor metrics in Search Console throughout the entire transition period