I can’t speak for the OP, but with the 15 drink daily limit includes non-alcoholic beverages, if someone drinks 8 to 10 bottled waters, along with some specialty coffee, that leaves 5 to 7 drinks, which is not a whole lot on a cruise if one also drinks at lunch, I would think. I myself have drank 2 glasses of wine at lunch, 2 cocktails at a bar before dinner, 2 wines at dinner, and then an after-dinner drink or two. Not something I do at home, but certainly on a cruise, on a sea day.