All products will last for 3-4 days if refrigerated. If not refrigerated, it all depends on the heat. Even in hot weather they will be good for 24 hrs (with the exception of Rehab, which should be consumed immediately or refrigerated). Beyond that I suggest the "sniff test". If it smells weird, throw it out!  The natural flavors we use dissipate quickly once mixed, the flavor only lasts for a few hours but they are still fine to drink.