How to detect if "Show end date" is checked? Trying to find a way to get the value of the checkbox "Show end date" on a date field on drupal 7.

Is it stored somewhere in the database? Can't find it. 
Its definitely not in the $node object.

Any ideas?
It's stored against the field settings in the field_config table. You can get access to it through the API with field_info_field()

$field_info = field_info_field('field_name');
$to_date_setting = $field_info['settings']['todate']; // optional, required, etc