Support for Drupal 7 is ending on 5 January 2025—it’s time to migrate to Drupal 10! Learn about the many benefits of Drupal 10 and find migration tools in our resource center.
Enforcing the max advance would save time when making reservations, but the node would still need to be saved to test the duration limits for the content type
http://eonasdan.github.io/bootstrap-datetimepicker/#example3