Just for fun, I wrote a simple plugin that tracks the number of emails sent with success, the number of failures, and the average time spent sending every single email.
All information is added to the Site Health page of WordPress (a less-known information page rich with interesting things about your site… you should check it out from time to time).
Download the zip package (named mail-stats-x.x.x.zip) from the releases page on GitHub and install it as a regular plugin.
It can even be used as “must-use” plugin by just dropping the file mail-stats.php into the wp-content/mu-plugins folder.
