It depends on the environment and usage. However, warming the lighter by carrying it in your pocket (the common usage) will speed evaporation. Here in Florida, I can expect about a week with little or no usage before the fuel evaporates. I'm a high tech type of guy, but I am strangely drawn to this low tech lighter and carry one every day even though I am not a smoker.

As for the canister, you can get one at http://www.smokerstuff.com/accessories/canister.htm