I don't know. I've known young women who sometimes cover and sometimes don't. I asked one of them why, and she laughed and said that if she was having a bad hair day, or had nothing clean to wear she would cover up, and if she'd just been to the hairdressers and had a new dress she wouldn't. A bit like people wearing crosses or St Christopher jewellery for fashion rather than religion, I suppose? Equally, I know that that is by no means always the case.
I'm conflicted, as I don't support anything that restricts women's freedoms, yet believe in freedom of religion. If a woman doesn't want any man but her husband to see her hair, or the outline of her body, or if she has strict rules about menstruation or whatever, I think she should be able to live by them with as little hindrance as is possible; but also that if someone is trying to force those strictures on her she should have protection.