A super quick blast from the past today; a Drupal 7 based article! I had some work recently to create a new "setting" variable for one our Drupal 7 multilingual sites, which meant creating multilingual versions of those variables. I soon found out that there is very much a correct way - or order - to achieve this as I got this one very wrong (I had to re-instate my DB!). So here I am...
Define a schema for any bespoke configuration, it's not too hard. It's needed to make it translatable, but Drupal 8 will also validate your config against it so it's still handy on non-translatable sites. As a schema ensures your configuration is valid, your code, or Drupal itself, can trip up without one. Set up a schema and you avoid those problems, and get robust validation for free. Hopefully my example YAML shows how it can be quite simple to do.