Do the daily yellow stains on the underwear due to intermittent urine drops count as incontinence, and must the underwear be changed before every prayer, or is a daily change sufficient, and is it necessary to place a tissue on the private parts, and what is the ruling on past prayers, knowing that these stains were present?

Purity of one's clothes, body, and place of prayer is a condition for the validity of prayer. It is obligatory to wash the area of impurity before prayer, or to change one's clothes, or to place a cloth over the penis and remove it at the time of prayer. If a person suffers from urinary incontinence, he must purify himself for each obligatory prayer (thoroughly wash the affected area, then bind the penis, then perform ablution). The subsequent discharge of urine will not harm him. He may perform supererogatory prayers with the ablution for the obligatory prayer until the time for the next obligatory prayer begins. If he knows that the incontinence will cease at a specific time, he must wait and pray at that time. The Malikis hold that an impurity that is continuous for most of the time does not nullify ablution, and it is not obligatory to wash it off. As for making up previous prayers, there are two opinions: the obligation to make them up (which is more cautious), or that it is not obligatory.