Why would there be a change? Seems an odd question.
To specifically answer your question, I'd prefer one that looks good during the day. At night I can always drink. :P
But, more seriously, I think it's a silly question. I love my Girlfriend for a whole host of reasons, and "looks" comes in about 8th. Now, she won't grace the front page of FHM any time soon, but she's also not going to appear on Freeks R Us either. My GF, like most women, is a nice looking average girl. She's healthy, she's not fat nor thin. She looks pretty. She's clearly out of my league and my mates tell me that... all... the... time. And I love her and think she's the best person in the world.
Realy hard. It's really not that simple. What are you getting at exactly. There are different scenarios. This is assuming you're with her the entire day. I think I would want her looking good when we usually get intimate, which for me is usually at night. But if we were both on an afternoon shift lets say, and we were hanging out during the day than I would want her looking good then. I've never had an issue of my girls looking that different between night and day. Why would there be such a difference unless you were a lot of makeup to cover your ugly face.
It's from an old story (sometimes as a Camelot/King Arthur tale, other times as a Charlemagne era poem) in which a knight is sent on a quest to discover what it is that women really want on pain of death if he can't figure it out. He discovers a hideous witch in a swamp (of course she lives in a swamp) who tells him that she can give him the answer in exchange for marriage. Eventually, he discovers that she is cursed to be ugly during the day and beautiful at night, and she tells him that he must choose when she is beautiful; day or night. In response, he says that it's her body, her choice, and in doing so breaks the spell so she can be beautiful both day and night.
The answer to the riddle of what women *really* want, then, is their own way!
That's as best as I can recall it anyways, it's been a long time since I read it.
I'd give her the choice (I'm also familiar with the original story)
In the event where she wanted me to choose, I'd say at night. In the original context it was a question of whether or not I'd rather have someone beautiful to be intimate with, or someone whom I can show off around town. In that case, at night because I wouldn't care what the townspeople thought, as I know what she'd really be like and that's how I'd see her. In the argument about her being worried what the townspeople think of her. I'd think that if the roles were reversed and she was choosing whether I'd be ugly during the day, or at night, I'd rather be ugly during the day. The reason is when I'm with her, I'd want her to actually want to be with me, and how she felt about me right then and there would completely trump what anyone else thought. I'd apply that thought process as well.