Brother Bomb. The glasses they GIVE you are free. They are called BCG (Birth-Controlled-Glasses) for one very simple reason. If you wear them, then there is NO CHANCE in hell that you will get any girl pregnant. And if you're a girl, then there's no chance anyone will get you pregnant. Hopefully that answers what the military will do for you, when it comes to the "Style" of glasses. But, as for buying some, you definitely can do that. And the military optometry even has some basic but decent styles "Compared to the BCG's". However; that is all after the fact of BCT. Glasses don't weigh anything. Bring both pairs if you want. If they forget your BCG glasses, use your beat up ones so they don't matter if you bang them up in the obstacle course or survival course. Have the newer/nicer ones so after BCT you will have a nice pair until you decide to keep them, buy a new pair, go with contacts, etc.... It could be a few weeks before you have the opportunity to go to an optometrist. as long as yours aren't Elton John style glasses, being them. If all you have is the old pair, then just bring those. You'll eventually get your BCG glasses and those will be fine until you get a better pair after BCT.