Boiling water for five days for one man with one 8 oz. (actually weighs 13 oz. because empty canister weighs 5 oz.) is pushing it IMHO.
Wow... I have done 10 days on a single small canister. I guess I was only cooking breakfast, coffee, and dinner, and that's with a jetboil.
Like Jordan said though... there are a lot of factors. If you don't have water and are melting snow, all bets are off - that's the only time I've run out of fuel (and the worst time to run out of fuel).
