Before my life had the rug well and truly pulled from under me i would have just four cans of Guinness and that was it.There are some good zero percent alcohol beers now which helped me cut right down. They even do guinness but it's not one of the better ones imho.
I'm doing eight or nine so not good, one night i had ten can's , the thing is as with everything else to do with alcohol, it's when you get to the don't give a fuck stage, then self control goes out the window.