A hosting move, platform migration and full redesign are not the same SEO event. The more URLs, content and technical signals you change at once, the more Google has to recrawl and reassess. Good migration work is about reducing unnecessary change and making every necessary change explicit.
A hosting move with the same URLs is relatively simple
If the domain, URLs and content remain the same and only the server changes, Google has far less to relearn. The main risks are downtime, slow responses, blocked crawling or technical mistakes during DNS/server setup.
URL changes need a proper map
If pages move to new addresses, map every important old URL to the most relevant new URL and use server-side permanent redirects. Do not redirect dozens of unrelated pages to the homepage simply to avoid 404s.
Keep useful content and signals
Preserve content that already performs, along with headings, internal links, metadata, canonical signals, structured data and image assets where appropriate. A migration is not the moment to delete half the site unless there is a clear content strategy behind it.
Expect some movement while Google recrawls
Google's own site-move guidance warns that rankings can fluctuate temporarily while the old and new URLs are recrawled and reindexed. That is different from saying “rankings are guaranteed to stay exactly the same”. The objective is to minimise avoidable loss and monitor the transition.
Use Search Console before and after
Keep access to Search Console, analytics and the old site's crawl data. Submit the new sitemap, monitor indexing/crawl errors, verify redirects and compare traffic/queries after launch. On a larger migration, retain the old URL map so unexpected losses can be traced.
Do not combine changes without a reason
Changing host, platform, design, URL structure, copy and domain on the same day creates more variables. Sometimes a complete change is necessary, but if you can preserve strong URLs and content while changing the underlying platform, that usually makes the move easier to diagnose.
Create a before-and-after benchmark
Before launch, save a crawl of the current site and record important landing pages, organic traffic, Search Console clicks/impressions and indexed URLs. That gives you something concrete to compare after the move. Without a benchmark, a normal seasonal traffic change can be mistaken for a migration problem, while a real missing redirect can go unnoticed.
Keep redirects in place long term
Permanent redirects are not a temporary launch-day patch. Google recommends keeping redirects for a long period, and users may continue following old bookmarks or links for years. Once the migration is stable, update your own internal links and major external/profile links to point directly to the new URLs, but keep the old-to-new redirects available rather than removing them after a few weeks.