How do the mountain huts work?

New Zealand has an excellent network of mountain huts, providing overnight shelter on its amazing hiking routes. These are not like huts in the Alps however where you can order a three course meal – you need to carry all your own food, and a stove to cook it with, along with a sleeping bag. Booking is required at huts on the more popular routes during the hiking season, and often places sell out many months in advance.