Musannaf Ibn Abi Shayba 1:1914

Hatim ibn Isma'il narrated to us, from 'Abd al-Rahman ibn Harmalah, who said: Sa'id ibn al-Musayyib said: "When you insert your feet into the khuff (leather socks) while they are both pure (in a state of wudu), and you are a resident, it suffices you until the same time the next day. And for the traveler, it is three nights."