So you're trying to decide if it's worth it to buy your own prom dresses. After all, you're going to only wear it one day. The question is—why should you buy your own formal dresses? How can it benefit you?
The answer is that by buying your own prom dress, you allow yourself the opportunity to have a formal dress always on hand. Now, you could buy a huge, fancy, completely out there dress, or you could buy something that is a little bit more conservative and that would serve you better for less formal dances. It's up to you. Make sure that if you are gong to buy your own prom dress is take the time to make sure that the dress fits you well and also doesn't poke or stab or do anything like that. Make sure that the fabric is very comfortable to you also. You don't want to be stuck in a dress for six plus hours that feels horrible.
When you buy your own prom dresses, you also are able to wear it wherever and whenever that you like. You are also able to mix and match it with whatever accessories that you would like. One tip when you buy a prom dress is to make sure that the dress is your favorite color or a color that you really, really like.