A pre-mixed cocktail with an alcohol by volume over 25% is good for 3 months if unopened and stored at room temperature. Once opened, you must refrigerate the beverage. It's typically good for 2 weeks in the refrigerator, but your cocktails will have the best flavor when consumed within a few days of opening.  If you want your spirits to last longer, it's best to purchase liquor and cocktail mixers separately. Any liquor with an ABV of 18% or more will not go bad, though you will still need to replenish your mixers regularly to make sure they stay fresh.