In reply to Lord Font:
Two years ago. They all still took cash only and the Swiss huts expect Swiss Francs. If this is still the case,get the SF before you get to Chamonix as it's expensive/impossible to find the cash currency as banks don't stock it.
Prepare yourself for ram packed huts. This brings odd issues like there are simply no phone/camera charging sockets. I was also amazed at how much alcohol people could get through at altitude, you will probably also have to eat in shifts.
The guardians do try their best.