Optimize old ineffective post or delete it and write better one with the same topic?

Have you tried to optimize your old ineffective posts so that after rewriting they ranked better? Or is it better to delete the old one and write new better-optimized one? (in case it has no backlinks). What results did you get? Share your experience, pls.

Yes, optimizing old posts is a good idea. If you delete it and move it to a new URL, consider 301ing the old URL. Unless you want to change the URL structure to be better optimized, there's probably no reason to delete and rewrite it entirely.