[Plugin: All in One SEO Pack] Should I fill in the SEO options appearing in every post?

Apart from the general options selected in the configuration panel of the plugin, is it worth placing title, description and keywords for each post, does this practice improves the positioning or is it a bit repetitive and makes no sense?

By the way, should I update every previous post published before this plugin was installed?

Thanks and regards,
Miguel

https://www.ads-software.com/extend/plugins/all-in-one-seo-pack/