Weddings on the islands, where everything from the stage to the ice arrives on a boat and there is no second trip.
The planning runs backwards from the sailing. Most islands have one or two cargo sailings a week, so the load has to be complete two days before it leaves and the list has to be right, because an item that is forgotten is not late, it is absent. We build that list with the family and we add the things nobody remembers: extension leads, spare bulbs, a first aid box, bin bags, and far more drinking water than anybody plans for.
Power is the other island problem. A stage, lights, a sound system and a caterer's warmers on a house supply will trip it, so anything over a hundred and fifty guests is quoted with a generator and fuel for twice the hours you think.
We charge our planning fee plus travel and accommodation at cost. Two of us go over the day before and we stay until the venue is clear.