If you are significantly reducing the number of products or pages on your site, it is generally best to keep your existing domain name rather than switching to a new one. Use 301 permanent redirects from old URLs to their new equivalents where appropriate to signal to Google that content has moved. However, it is acceptable to let some obsolete pages return 404 errors if they no longer have relevant replacements. This approach helps avoid unnecessary redirect chains and reduces the risk of losing traffic due to migration errors. Focus on redirecting only what is necessary and allow Google to drop truly obsolete pages naturally. [Google]