How to keep your SEO when changing addresses
Changing a page's address can wipe out years of search value overnight. A correctly set up 301 redirect prevents that.
A client who had redesigned their site wrote to me three months later: "Traffic from search has almost stopped." The site looked good, it was fast and everything worked. None of the old addresses had been redirected to the new ones, though.
Google still knew the old addresses. They returned 404 and gradually dropped out of the rankings, while the new addresses started from zero.
The difference between 301 and 302
301 means the page has moved permanently. Google passes the value the old address built up to the new one and eventually drops the old one from its index.
302 means the page is somewhere else for now. Google expects you to come back, so it doesn't pass the value on.
If you're not coming back, use 301. For something that really is temporary, like a campaign page, 302 is right. Use 302 for a permanent move and the old address's value never reaches the new one.
A checklist for redesigns
1. Export the old addresses
Before you switch, list every address on the current site. The Pages report in Search Console and your old sitemap will give you that list.
2. Build a mapping table
Write the new address next to each old one. Where there's no direct equivalent, pick the closest parent page. Don't send everything to the home page in bulk, because Google treats that as a "soft 404" and passes nothing on.
3. Set up the redirects and test them
Once they're in place, pick ten addresses at random and open them in a browser. Check that each one reaches the right page in a single hop.
4. Update internal links
Links inside your site should point straight at the new address. Going through a redirect still works, but it adds an extra request every time.
Avoid redirect chains
If A redirects to B and B redirects to C, the browser makes three requests. That slows the page down and loses a little value at each step.
When you change an old redirect's destination, point it straight at the final target instead of adding another link to the chain.
How long does recovery take?
Google takes weeks to process redirects. A dip in traffic for the first few weeks is normal, and if the redirects are set up correctly it recovers.
Keep redirects in place for at least a year. Old links live on in other sites, emails and bookmarks.
On this site you set up redirects from the admin panel, and it counts how many times each one is used, so you can see which old addresses still get traffic.