The gemoro and shulchan aruch has much to say about 'vestos', way to find out in advance when one will be a niddah, which rarely work today. There are modern methods which do work: does one have to ...
Can a woman delay going to the Mikvah on her Mikvah night? That is, if it is the seventh day and she is scheduled to go to the Mikvah, but it turns out to be inconvenient (for example if a friend's ...
If a woman was a "ro'eh machmis tashmish" (she saw blood after having relations), does the day that it happened go into the account of her "vestes" (the days that she will have to be concerned she may ...