A business moved to a new website and kept the same domain. Traffic dropped by about a third and stayed there. The new site was better in every visible way.
The page addresses had changed. Every link Google held, every link on another site, every bookmark and every link in an old email now led to a “page not found”.
Why nobody noticed
Everyone who tested the new site started from the homepage and clicked around, and from the homepage everything worked. Nobody arrives from the homepage in real life. They arrive on a specific page, from a search result written months ago.
The people hitting those dead pages did not complain either. They pressed back and chose a competitor, which produces no signal whatsoever.
The fix, and the better fix
Every old address was mapped to its closest equivalent on the new site as a permanent redirect. Anyone following an old link now lands on the right page instead of an apology. Most of the lost traffic returned over the following weeks.
The better fix belongs before launch, not after: export the old site’s addresses, decide where each one should point, and put the redirects live at the same moment as the new site. It is an hour of unglamorous work that prevents the entire problem.
Worth doing today
If you have changed site in the last couple of years, open Google Search Console and look at the pages report for “not found” errors. That list is a direct record of people arriving and hitting a wall.
If you are about to commission a rebuild, ask one question before signing: what happens to the existing addresses? A good answer describes a redirect map. A vague one is a warning worth heeding, and it belongs alongside the other things to settle before anyone starts.
Worth knowing too that a rebuild is not always the right response to a quiet site. Some sites are losing people after they arrive, which is a different problem entirely.
If traffic fell after a move and never came back, describe when it changed. It is usually recoverable.