A redesign is a chance to improve the experience, but changing URLs and content can also remove signals that took time to build. Treat search continuity as part of the project plan.
Inventory before changing
Record important URLs, traffic, queries, links, titles, redirects, and pages that generate enquiries. Map old URLs to the closest useful new destination. Do not redirect everything to the homepage.
Test the release
Check canonicals, status codes, internal links, sitemap, robots rules, structured data, mobile layouts, and forms on the new version. Monitor both search data and real enquiries after launch.
Technical SEO support can be included before and after the redesign.