Picture the room when the first notes hit the back wall during the main course. A live string duo changes the entire weight of a weekday dinner party, turning a simple meal into something people talk about for weeks.
Because you are booking a live act for a specific night, lead-time is your real leverage. Musicians book out months ahead for weekend slots, but weekday dates give you room to negotiate and lock in the right players before your calendar fills up.
Remember that the 18-month window is a hard deadline, not free money. If you still have a balance left on the card when that period ends, interest kicks in on the remaining amount.