Automated Cache Busting. This works by adding the file's change time to the end of the URL (last argument of the call)

wp-automated-cache-busting.php

<?php

  /* For Themes */
  wp_enqueue_style('slug', get_template_directory_uri().'/css/slug.css', array(), filemtime(get_template_directory().'/css/slug.css'));
  wp_enqueue_script('slug', get_template_directory_uri().'/js/slug.js', array(), filemtime(get_template_directory().'/js/slug.js'));
  
  /* For Plugins */
  wp_enqueue_style('slug', plugin_dir_url(__FILE__).'css/slug.css', array(), filemtime(plugin_dir_path(__FILE__).'css/slug.css'));
  wp_enqueue_script('slug', plugin_dir_url(__FILE__).'js/slug.js', array(), filemtime(plugin_dir_path(__FILE__).'js/slug.js'));

?>