IMO no rules for a woman just be aware of the vibe you might be giving off. There were times I got in a back and forth with someone at night and other times the woman would take her time to respond. If I got into a back and forth with multiple messages exchanged in one evening usually I would meet them out for drinks faster than I would someone who took a day to respond. It just depends on how fast you want to move. Women that took their time to respond where more intriguing to me.
The DR. read my message on a Saturday, she responded the next day (Sunday) and we met out for drinks on Wednesday.
I expected most people would respond at night after they got off of work. Remember that you control the pace.
