How many beers do you get out of a CO2 tank

[VictimKBrew]

Just bought a dual tap kegerator. How many beers do you get out of a 5lb CO2 tank? Also - (this might be a stupid question) when the tank is empty does it affect the beer? Should I buy a second tank to have on hand?

 

[BoatsAndBrews]

I get about 4-5 kegs out of my 5lb co2 bottles. Having an empty co2 bottle does not seem to affect flavor, but with no co2 it won't pour....

I would definatly get another co2 bottle nothing sucks more then running out of co2 when its too late at night to buy more.