"You don't owe prettiness to anyone. Not to your boyfriend/spouse/partner, not to your co-workers, especially not to random men on the street. You don't owe it to your mother, you don't owe it to your children, you don't owe it to civilization in general. Prettiness is not a rent you pay for occupying a space marked "female".
I'm not saying that you shouldn't be pretty if you want to. (You don't owe un-prettiness to feminism, in other words.) Pretty is pleasant, and fun, and satisfying, and makes people smile, often even at you. But in the hierarchy of importance, pretty stands several rungs down from happy, is way below healthy, and if done as a penance, or an obligation, can be so far away from independent that you may have to squint really hard to see it in the haze.
But what does you-don't-have-to-be-pretty mean in practical, everyday terms? It means that you don't have to apologize for wearing things that are held to be "unflattering" or "unfashionable" -- especially if, in fact, they make you happy on some level deeper than just being pretty does. So what if your favorite color isn't a "good" color on you? So what if you are "too fat" (by some arbitrary measure) for a sleeveless top? If you are clean, are covered enough to avoid a citation for public indecency, and have bandaged any open wounds, you can wear any color or style you please, if it makes you happy..."
-- Erin McKean