I used to carry Zippos when i smoked (I am trying to quit right now so I am not carrying a lighter anyway) I used the leather Zippo holder but I TIG welded the clip together at the bottom so it can't come off. (I seem to have a problem with clips just refer to my Leatherman warranty post). I had a nylon holder years ago but don't know what happened to it. I actually wore out one of the leather holders and had to replace it after about 4 years or so.
I kept zippo fluid in every vehicle and in my tool box and lunch box so i could always refill. Now that i think about it I need to take the bottle of fluid out of my hunting waist pack.
I love Zippos I must have a dozen or so and some of them are unused. I even have my dad's from the 60s or 70s and a few of the belt buckles to keep them in

Kirby