If you carry a Zippo around as a normal course of action then you may as well consider it a piece of your survival gear. I personally do carry a Zippo most days but always have a backup Bic in the kit. Another nice thing about a classic Zippo is that, when flying, they are allowed on your person or Carry-on luggage filled with fluid whereas compressed gas lighters are not.

That said there are a number of options to keep your Zippo more reliable. As has been said before; always keep a spare flint under the flap at the bottom of the lighter. (some Zippo's have a hole just for placing a flint)

Zippo offers a container just for the purpose of holding spare flint and fluid which would be something great to consider if you do normally carry a Zippo with you: Zippo Fuel Canister Key Chain Cost is around $15 and has provisions for storage of 2 flints, one refill of fluid, and even a flat portion for loosening the screw that retains the flint.

Possibly a better option is the Zippo BLU which is a butane-powered jet-type lighter. Keeps the basic feel of a classic Zippo with more reliability of butane. Zippo BLU product page
Zippo BLU Introduction videos


I also believe that I recall seeing a butane-insert for standard Zippo's over at County Comm.