How do I know if my trailer coupler is adjusted correctly?

I own 2 trailers, and half of 2 others. And none of them like the same drop on the ballmount, or ball. When we unhook we pull the ballmount, stick the ball back in coupler, and lock it. When ready to hook up, we know the latch is open, because we just pulled the ball out. The surfaces that dirt would harm if it collected are protecting each other from dirt. The trailers are parked where little foot traffic so unlikely somebody will decide need the mount.