Many a maturing woman seems to develope small vertical wrinkles just under her nose and "crinkling" along her upper lip because they typically do not shave there every day.

Men regardless of age who shave regularly do not have this problem as shaving removes, with whiskers, an upper level of epidermis and keeps that area wrinkle-free.

If this same principle applies to female genitalia one more educated than I might have the answer. Still, it's worth considering given the two quotes by redEva and woodman's game:
Keep doing it every day
and
The more you do it the better it is