I always come in and go out of the doors to the outside looking DOWN. I can't realistically do a head count any more, I'd never find them all and by the time I did I would forget who I counted. But I always look around before I leave and shoo them from the door and go in extra carefully.
I do not have "door runners", but I never allow the door to stand open. I step all the way out even if it is just for the pizza delivery person and close the screen/storm door behind me.