How to detect if an ACF custom-field is really in use?
Most sensible here is probably just a custom query global $wpdb; $sql_find_meta = “SELECT post_id FROM database_name_here.wp_postmeta WHERE meta_key = ‘my_special_value’ AND meta_value > ”;”; // > ” == not null, whitespace or blank $posts_with_meta_key = $wpdb->get_col( $sql_find_meta ); foreach ( $posts_with_meta_key as etc….. You can repeat this for wp_termmeta and term_id