In reply to phja:
For busy, honeypot huts, you will almost certainly have to book. If they are in remote serious mountain terrain they are not supposed to turn you away if the situation is threatening, but where there is a straightforward path down to the valley and you have just walked up on spec and are in no way impaired, they can and may do so. For more outlying huts in less popular situations booking is less necessary but still courteous. Sometimes if they have to put you up unbooked or because you arrive late after a route and are too tired to go down safely, you may finish up on a mattress on the floor. Or just on the floor.
Normally booking is over the phone, though almost all huts have websites now. To cancel, you just phone up and do that, there is normally no deposit. But with for example the Dom hut, they will ask you for your credit card no on booking, not sure how late they will accept a cancellation. How late a cancellation will be acceptable will partly depend on if you have ordered food, typically much after 2 or 3 in the afternoon will not leave you popular.
Most huts, certainly including Albert 1 will do food, almost always you can cook your own if you want, not necessarily very conveniently as they prefer food-buying clients. The hut guardians normally make most of their income from food, either from climbers or tourists who visit the hut during the day, for night stays they are largely just acting as agents for the various Alpine clubs that own most of the huts.
