JordiPlana

This plugin hooks the normal WordPress workflow in order to determine if the request is processing will cause a 404 HTTP error. In that case it prevents WordPress to do any other processing and sends the user to the page defined in the plugin options.
A working and simple solution.
For more information about this plugin you can check <a href="http://jordiplana.com/404-simple-redirect-plugin-for-wordpress" title="404 Simple Redirect Plugin for WordPress" rel="nofollow ugc">the official page</a>.

404 Simple Redirect

This plugin hooks the normal Wordpress workflow in order to determine if the request is processing will cause a 404 HTTP error.

Good caching policies is one of performance’s best friends, and it can be your new best friend too. Get friendly with intermediary and browser caches by taking control over your WordPress powered website’s HTTP <code>Cache-Control</code> headers.
This is not a caching plugin in itself, but will enable you to leverage existing standard compliant caching systems better. You can set different policies for different kinds of pages to suite your website’s needs. The Cache-Control for WordPress plugin allows you to set different policies for shared/intermediary and private caches. The plugin sets some sensible defaults for a medium traffic blog that publishes an update or two per week.
You can safely set long <code>Cache-Control</code> times as the <code>max-age</code> values is lowered automatically before a scheduled post is about to be published.
Private pages (logged in users, the admin interface, etc.) will not be cached.
The plugin has <a href="https://www.ctrl.blog/entry/wp-cache-control-documentation.html" rel="nofollow ugc">extensive documentation</a>.

Cache-Control

Configurable HTTP Cache-Control response headers for webpages generated by WordPress.

404 Simple Redirect vs Cache-Control