What is the religious ruling on discovering past errors in acts of worship, such as the wording of the Tashahhud or ablution after urination, and what should be done with the continued discovery of such errors?

The Tashahhud has several established forms. Whichever form a Muslim recites for the Tashahhud will suffice him. Scholars have differed regarding the obligation of the first and second Tashahhud. The Malikis hold that both are sunnah and the prayer is not invalidated by omitting them, especially for someone who has an excuse. If someone prays in a garment that is impure, being ignorant of the impurity, he is not required to repeat the prayer, according to the preponderant opinion. It is obligatory for a Muslim to learn what corrects his prayer, for this knowledge is an individual obligation (fardh 'ayn).