>>1413923Having a reservation is recommended, but there is different huts. Some huts are only open in summer, some are in winter to, some have full service, some are emergency shelters. Most have bunks and you'll need to bring your own sleeping bag, and if you are an SAC member or it's a private hut, you can get the keys for winter, the hut is yours, you can use the gas and the beverages (write it up) and only have to bring your own food.
https://www.sac-cas.ch/en/huts-and-tours/route-portal/ 