There are two ways that those beer hero's at you favourite brewery put the liquid gold you love so much into a bottle.  

-These bottles are purged with CO2 gas before filling and once filled will keep for 2-3 months.  Once opened they should be consumed within 1-2 days.
They do not require refrigeration for storage.

-These bottles are filled straight from the draft handle. From filling the beer is best if drank within 3-4 days.  Once opened they should be consumed in one sitting as the carbonation is lost by the next day.
These beers should not be left out of the fridge.

Be aware of the filling style when you order.  Going to drink it soon? Draft is great!!  Want to keep it for a bit? Get some of that CO2 charged goodness!!