What does the state of excuse (uzur) mean, and when does a person with such an excuse perform ablution (wudu)?

In Islamic jurisprudence, the concept of "uzur" (excuse) is most frequently used in relation to conditions that continuously invalidate ablution. Persistent nosebleeds, urinary incontinence, constant vomiting, flatulence, continuous bleeding or discharge from a wound, and women's istihada (non-menstrual bleeding) are examples of bodily conditions that invalidate ablution and are ongoing; these are called "uzur," and those who have such conditions are referred to as "uzur sahib" (person with an excuse). (Kâsânî, Bedâ’i, 1/28, 29; Marghinani, al-Hidaya, 1/34; Ibn Abidin, Radd al-Muhtar, 1/305)

For a person to be considered as having an excuse in matters of worship, the excuse must persist throughout an entire prayer time without ceasing long enough to perform ablution and pray, and it must recur at least once in every prayer time. The state of excuse ends if the cause ceases for the duration of a complete prayer time. (Ibn Abidin, Radd al-Muhtar, 1/305-306)

According to the Hanafi school, a person with an excuse performs ablution for each prayer time. This is because the Prophet Muhammad (peace be upon him) instructed a woman with such a condition to do so. (Bukhari, Wudu’, 63 [228]) Unless something else that invalidates ablution occurs apart from the excuse, the person may perform as many obligatory, necessary, sunnah, or make-up prayers, as well as Friday and Eid prayers, circumambulate the Kaaba, and touch the Mushaf with the ablution taken during that prayer time. (Marghinani, al-Hidaya, 1/34) However, the ablution of a person with an excuse is nullified when the prayer time ends, so they must perform ablution again for the next prayer time.

The ablution of a person with an excuse is also nullified by anything else that would normally invalidate ablution, apart from the excuse itself. (Kâsânî, Bedâ’i, 1/28) For example, if a person considered excused due to urinary incontinence experiences a nosebleed or passes wind, their ablution is invalidated.

According to Imam Shafi'i, a person with an excuse must perform a separate ablution for each obligatory prayer within a prayer time, as their ablution ends when the prayer is completed. With this ablution, they may perform as many voluntary prayers as they wish. (Shirbini, Mughni al-Muhtaj, 1/282)

According to the Maliki school, the ablution of a person with an excuse is not invalidated by the entrance or end of a prayer time, but only by something other than the excuse that would normally invalidate ablution. (Ibn Rushd, Bidayat al-Mujtahid, 1/41; Desuqi, Hashiya, 1/114-118)

If the state of excuse causes a person significant hardship or serious difficulty in performing ablution, it is permissible to follow this Maliki opinion.

Source: T.C. Diyanet İşleri Başkanlığı, Din İşleri Yüksek Kurulu