Solution: Fact: Braids last longer in dirty hair. The natural oils give twists something to adhere to. If your hair gets too greasy, douse your roots with dry shampoo like Dove's (available in March, $4; drugstores) and you’ll be good to go.
Another way to add staying power is to try a more intricate plait like the fishtail braid Minka Kelly wore, the step by step on this super pretty style here.