as most of you probably know vitamins don't do anything by themselves. you can take all the vitamins you want in the world but if you don't eat healthy and take care of yourselves then your just wasting money. vitamins only assist in the uptake of essential minerals. So taking vitamin D alone won't make your bones stronger but the interaction of vitamin d and calcium. Vitamin D helps your body absorb calcium at great efficiency so you maximize what you input. Eating a large number 1 and then going home later and taking your vitamins aren't going to do anything. Therefore as hobi said YMMV. Another note vitamins need to be taken consistently over a long period of time for your body to start to naturally increase its efficiency. so it's a good idea to stock up if you can.