/**
* Force all the users autoship orders to be updated if the user
* Changes their address info.
*
* @param bool $update The current update flag. True updates all orders, false doesn't
* @param int $user_id The current users id.
*
* @return bool The filtered update flag.
*/
function xx_always_update_my_autoship_scheduled_orders( $update, $user_id ){

  // Add custom code here
  // ex. add a custom "Always apply to my orders" checkbox to user's account
  // and retieve the value from the user's metadata
  $should_update = get_user_meta($user_id, 'my_custom_user_field_always_update', true );
  return empty( $should_update ) ? $udpate : $should_update;

}
add_filter('autoship_apply_to_scheduled_orders_by_default', 'xx_always_update_my_autoship_scheduled_orders', 10, 2 );