Zippo has changed their manufacturing process over the past few years which has caused a problem with some people when they acquire a new Zippo lighter for the first time. After filling the lighter with fluid, after a couple days it seems to run out of fluid and has to be refilled again.
The problem isn't that it is running out of fluid necessarily, it may just be that the wick is unable to draw the fluid up efficiently.
I will show you a simple solution to fix this very common problem, and get the Zippo set up like it was supposed to be when it was shipped from the factory. This will only take you a few minutes to do, and the only tool that you need will be a pair of needle-nose pliers or long tweezers.