Is it obligatory to repeat past prayers in which one wiped over a perforated leather sock (khuff), or wiped over it without being in a state of purity (tahara), for a period exceeding two years?

Wiping over leather socks (khuff) is only valid if they were put on after a water ablution (taharah ma'iyyah), according to the majority of scholars. If they were put on while in a state of impurity (hadath) or after a dry ablution (tayammum), the ablution (wudu') is not valid, and the prayers must be repeated.

As for a torn leather sock: the fatwa we adopt is that wiping over it is permissible if the tear is minor, and the ablution performed with it is valid, meaning there is no need to repeat the prayers.