My boyfriend likes seeing me wear a dress and he likes it when I don't wear my glasses but I feel more comfortable with glasses than contacts usually unless I am going out and I also prefer to wear a dress for special occasions only
It's nice to do things for your SO but if you feel comfortable with what you wear just let him know that you prefer wearing your glasses (what guy has a problem with a girl wearing glasses?) and that you only like to wear dresses occasionally.
The word "should" implies some sort of obligation. The answer is no. You are not obligated to dress for him. If you want to do it then fine. But you are not obligated. He shouldn't pressure you to do it either.
You should only do whatever you want to do, your boyfriend should want you to be comfortable. there's a time and place where you have to dress more formal, however in the end you need to be in your element.
If and when she wants/feels the desire to :) Don't feel obligated to do it all the time. Sometimes in the "normal" days we just aren't in the mood to spend hours in front of the mirror, and that's ok. It shouldn't be a big deal as long as you still care about yourself and your appearance in general. :)