I love my Ziipo --- about 30years old!!!
Still also carry a cheap disposable butane, but thier failure rate is way to high to not carry a Zippo ( and matches) too. Carry wooden stick matched in a seal plastic pouch I make from my wife's kitchen food vacumn sealler--never leaks and lasts for years!

Yes, Zippos do lose fluid due to evaporation. I keep a can a fluid in my pick up and squirt a little into the Zippo every few times I go into the woods. Also, if you hold it upside down and pull the outer sleeve up off it, you can store extra flints on top of the wick material so as to never be without a spark!