It depends on how you are using the words. If you say, "He sold the books door to door" you mean he sold them ffrom door to door. He is then a door-to-door salesman. The hyphens are put in because...
"Latches" please Give more detail. The latches I assume you are referring to the handles. The latches or handles are on the door(s) because. Automatic doors need to have a secondary method of...