What does the condition of being excused mean and when should an excused person perform ablution?
Situations that nullify ablution incessantly are the issues in which the concept of excuse is mostly used in fiqh. Physical disorders such as continuous nose bleeding, urine incontinence and leakage, continuous vomiting, passing wind, continuous bleeding and leakage of a wound, and istihadha (abnormal menstrual bleeding) are called “excuses”, and the people who have such conditions are called “ excused persons”. (Kasani, Bada’i, I, 28, 29; Marghinani, al-Hidayah, I, 217-219; Ibn Abidin, Radd al-Muhtar, I, 504).
For a person to be deemed as excused, his/her excuse should not cease within one prayer time even for a while to perform ablution and establish prayer, and it should repeat at least once in every prayer time. The condition of being excused ends when the cause of excuse ceases for a complete prayer time (Ibn Abidin, Radd al-Muhtar, I, 504-505).
In Hanafi school, an excused person performs ablution in each prayer time because the Prophet Muhammad (saw) told an excused woman to do so (Bukhari, Wudu’, 63). An excused person can establish fardh, wajib, sunnah, qada, Friday, and eid prayers as much as s/he wants in the same prayer time, can circumambulate the Ka’bah and touch the Qur’an with that ablution by assuming that the ablution is not invalidated by the condition of being excused, and unless another condition to invalidate ablution happens. (Marghinani, al-Hidayah, I, 219-220). However, the ablution of the excused person is nullified when the prayer time ends. Therefore, the excused person needs to perform ablution again in the next prayer time.
The ablution of the excused person is also invalidated by the things that nullify ablution other than the excuse (Kasani, Bada’i, I, 28). For example, the ablution of a person whose excuse is urine incontinence is nullified if his nose bleeds or he passes wind.
According to Imam Shafi’i, an excused person needs to perform ablution separately for each fardh prayer to be established in the same prayer time. Because his ablution ends when his prayer is over. Yet, he may establish voluntary (nafl) prayers as much as he wants with this ablution (Shirbini, Mughni al-muhtaj, I, 175).
According to the Maliki school, the ablution of an excused person is not nullified by the beginning and end of the prayer time but by the things that invalidate ablution other than the excuse (Ibn Rushd, Bidayah, I, 35; Dasuqi, Hashiyah, I, 114-118).
In the event that the excuse of a person causes an extreme hardship to him/her and s/he has serious difficulties while performing ablution, s/he may act by this view of the Maliki school.
Source: Presidency Of Religious Affairs The Turkey, High Board of Religious Affairs FATWAS