Simply put - call to book the mohel as soon as possible after the baby is born. If you have parents, call them first to tell them about their new grandson. Then call the mohel.
The reason you can call after the baby is born is because we are accustomed to working on a short term basis - that is the nature of this line of work. As one colleague put it, "I never really know more than a week at a time if I will ever work again."
* the way the mother is carrying
* which foot she steps with first
* if she turns to the left
* if she has an aversion to chicken
"Yes," says Dad to Be. "So the baby is expected around four months from now. Will you be around?"
"Well," I answer, "No one seems to have called me yet for that date, so there is a chance..."
"Pencil it in your calendar, will ya?"