Site redesign
A redesign changes the design, structure, or technology of an existing site. Without an SEO component, a single launch regularly destroys years of rankings — changed URLs, removed content, degraded load times.
In practice
The minimum precautions: freeze an inventory of ranking pages before work begins, treat the redirect mapping as a blocking deliverable, and compare Core Web Vitals before and after on the same page templates. The question to ask for every removed page: who was looking for it, and where are we sending them now?