How can the duration of menstruation be determined and how can purity be distinguished from the subsequent yellowish and brownish discharges, knowing that menstruation does not begin at a fixed time of day, and that dryness, yellowish, and brownish discharges may intersperse the menstrual period and the blood may not be continuous?

The custom (habit) is established according to the Hanbalis by the repetition of blood three times, and its continuity is not required. What is repeated three times becomes a habit. If a woman sees blood during the possible time, it is considered menstruation. A woman is considered to have a habit if she knows her month in which she menstruates and becomes pure, and she knows the time of her menstruation and her purity from it, and her menstruation has been repeated for three months.

If a woman has known days for blood, these are her days of habit. If these days pass and she sees purity, she should not pay attention to any yellowish or brownish discharge after that. If the blood stops during the days of habit, she should perform ghusl. If the blood, yellowish, or brownish discharge returns, she becomes a menstruating woman again as long as she is within the period of her habit. Yellowish or brownish discharge connected to blood is considered menstruation, even if it appears after the end of the habit period.

If she sees purity by one of its two signs (dryness or the white discharge), she is not required to investigate further. The determining factor is the appearance of blood or yellowish discharge to the outer vulva.