A question often asked is how much fuel do you need. This depends a bit on how you cook, how much cooking you do, what fuel you are using, and whether you have to melt snow. For two people in summer, with a cup of tea in the morning and dinner of soup and a main course at night, I found about 60 - 70 mL (~50 gm) of petrol or kero per day to be sufficient, while about 30 gms of gas was enough. If you are using metho, double the Shellite quantities at least, and have some spare. In winter in the snow those figures need to go up for several reasons. The water is colder to start with (but this is a relatively small effect) and you may want more hot drinks. As well, you need a safety margin for melting snow.
These figures assumes you are using the fuel-saving tricks mentioned above - but eating fairly well. We were using about 35 g of gas for two people per day while ski-touring without melting snow; but I would normally carry a 50% safety margin in the snow just in case