Do you have friends? Do you want any more?
You will NEVER have any trouble whatsoever using your beer. A keg produces about 50 + or - 12 ounce bottles, probably around 35 + or - pints (foam etc... it never really works out to the full 40 you 'ought to get'.
If you have one or two pints a night, you'll go through the keg in a month. Frankly it's just starting to get really good by then. (Hence the 2 or 3 kegs to 'slow you down a bit.') That doesn't even take into account the buddies you'll gather who want to come over and enjoy a beer now and then.