I get about 20 kegs from a 10 pound cylinder. I keep my co2 outside in room temperature now, used to house it in the keezer. Found it emptied quite quickly, found many leaks in the lines. I've learned to keep refrigerated side connections to a minimum, no extra manifolds or valves (especially poly fittings which shrink in cold temps).
Use frothed up star san or soap solution to
apply to fittings with brush or spray bottle to check for leaks. Even a
small one can be costly.