493. Women with the habit of time are of two types:
1. A woman who observes the blood of ÎayÃ (starting) at a particular date in two consecutive months, and after a few days she is purified from it. However the duration of her ÎayÃ is not the same in both months. An example of this would be a woman who observes blood on the first day of the month in two consecutive months. However she is purified from it on the seventh day in the first month and on the eight day in the second month. Such a woman should consider the first day of the month as her habitual time for ÎayÃ.
2. A woman who observes the blood of ÎayÃ for three or more days (starting) at a particular time in two consecutive months, and is then purified from it. She then observes blood once again and the sum of all the days she observes blood along with the interval of purity does not exceed ten days, provided that the sum in the second month is more or less than the first month. For example, the sum of the days is eight days in the first month and nine days in the second month. Such a woman should also consider the first day of the month as her habitual time for ÎayÃ.
494. If a woman with the habit of time observes blood on her habitual date, or a little before it—albeit to an extent that the common understanding would consider her menses to be early—or a little after her habitual date—albeit to an extent that the common understanding would consider her menses to be late—she should act according to the rulings that were mentioned for a ÎÁÞiÃ, even if the blood does not possess the qualities of ÎayÃ. If she later realizes that it was not ÎayÃ—for example, she is purified from the bleeding before completing three days—she should offer the qaÃÁ of the rituals of worship that she had not performed.
495. If a woman with the habit of time observes blood for more than ten days, and is unable to distinguish ÎayÃ from its qualities, she should consider the habitual duration of her relatives as her duration of ÎayÃ, be they paternal or maternal, dead or alive. Obligatory precaution dictates that if their habitual duration is not six or seven days, she should combine the prohibitions of a ÎÁÞiÃ with the obligations of a mustaÎÁÃah during the difference between their days and six or seven days. However, she can only consider their habitual duration to be her own if all of their durations are the same. If their durations are not the same—for example, some have a habitual duration of five days and some seven days—she cannot consider their habit to be her own in ÎayÃ.
496. A woman with the habit of time who considers the habitual duration of her relatives to be her own, should consider the day which marks the beginning of her habit every month as the beginning of her ÎayÃ. For example, a woman who used to observe blood on the first day of the month, and would be purified from it sometimes on the seventh and sometimes on the eighth; if she observes blood for twelve days in one month, and the habitual duration of her relatives is seven days, she should consider it as ÎayÃ during the first seven days of the month and istiÎÁÃah during the rest.
497. If a woman who must consider the habitual duration of her relatives to be her own, does not have any relatives, or if they do not share a similar duration, obligatory precaution dictates that every month she should consider the first day she observes blood to the sixth or seventh day as ÎayÃ, and the rest as istiÎÁÃah.