Co2
 

how long is everyone finding a 5lb tank of C02 lasting? seems to be only 4-5 kegs for me.... worried I have a leak...

Not sure, but that seems a little low. Leak test all your fittings including the regulator, and get a 20# tank. They are cheaper to fill, and last forever.

Force carbing or just serving? You'll get a lot more out of them if it is just serving. If you're force carbing, you're probably OK.

i just carb and roll at 40psi

I think I got about 6 out of mine, but I had done a few tests, so I'm not sure exactly.
If you're force carbing at 40psi, and serving at the same pressure, that sounds right.