Very rarely ever use the horn but there is a couple of situations that I will use it every time.  I someone is walking alongside the hwy or riding a bicycle, I will lightly honk the horn about a half block before I get to them. Lets them know I am back there and still not close enough to startle the,  At night when approaching a truck from the rear, I will flash my high beams once so that he will know I am coming around him.  Old habits linger on.