Look the program over and plan an itinerary before you begin your activities. It's impossible to see everything, so pick two or three indoor performances and plan back-up options. Events start at scheduled times. There is no reserved seating.
Late admission is rare and at the discretion of each site's management.
All venues are cleared between performances. Allow ample time to get from one location to the next. First Night events usually attract a full house and locations close to Copley Square and Boston Common fill up quickly. Try sites off the beaten path. The performance you see by chance could be your favorite.