JuanMoore
Getting the banned back together
OK,
so Gary says that the big reason NOT to store your CO2 cylinder inside your kegerator, is that when your gauge reads empty, there is really still a third of the tank left, and when you go to exchange it, you are giving away a third of the tank full. Thus every three tank swaps, you're giving away a full tank worth of gas. Plus its one less keg you can fit.
TD
As I suspected, Gary doesn't understand basic fluid mechanics very well. If you go by the red "order gas" section on the gauge, it will likely tell you that you need a refill as soon as the tank cools to beer serving temps. If you let the needle go all the way to serving pressure or below, there will be more gas in a cold tank than a warm tank, but just barely, and certainly nowhere near 1/3 of a tank. The difference will be barely enough to serve a couple pints.