you can just look at the label on the bottle when the "best before" date is. if they're manufactured this year its usually good for a few years (like 3-4)
As long as you store them in a dry cool place...like a cabinet...don't worry about the date...they will be fine. I have some drol from 2006 and they are still fine since they have been stored properly.
Yep, Muscle addiction said it. I never pay attention to expiration dates or anything like that. If you store your gear correctly, it will be just as good years from now. Storing it incorrectly like in sunlight, moist areas, or heat can make your gear less potent and lessen its effects way before your expiration date too. It all comes down to storage