For anyone who doubts something in their wudu while still seated in the place of wudu, they should redo it. However, if they have already left the place and then doubt something about the wudu, they should disregard the doubt unless they are certain. If a person is certain of a state of ritual impurity (hadath) but doubts whether they performed wudu, they should perform wudu. Conversely, if one is certain of wudu but doubts an act that would invalidate it, they should not negate their certainty due to doubt unless they are certain. If one is sure of both wudu and impurity but does not know which came first, they should perform wudu.