He ﷺ would wipe over the leather socks both while travelling and while residing. For a resident he set a limit of one day and one night, and for a traveller three days and their nights, provided the person had performed ablution and then put on the leather socks, as stated in the ḥadīth of Abū Bakrah recorded by al-Dāraquṭnī (71) with a ḥasan chain. The period is counted from the moment of the first wiping until the corresponding time on the following day; this is the view of Aḥmad, as related in Masāʾil Abī Dāwūd (10).

No time limit applies, however, to a traveller whose duties would be hampered by repeatedly removing and putting on the socks—such as a mounted courier dispatched for the Muslims’ benefit—and the incident of ʿUqbah ibn ʿĀmir is to be understood on this basis. So stated Shaykh al-Islām in al-Ikhtiyārāt (9). The incident referred to is the report narrated by al-Dāraquṭnī (72) through ʿAlī ibn Rabāḥ, in which ʿUqbah said: “I left Syria for Madinah on a Friday and entered Madinah on a Friday. I went in to see ʿUmar ibn al-Khaṭṭāb”—another version adds, “and I was wearing a pair of those thick leather socks”—“He asked, ‘When did you put your feet into your socks?’ I replied, ‘On Friday.’ He said, ‘Have you removed them since then?’ I said, ‘No.’ He said, ‘You have followed the Sunnah.’” Al-Dāraquṭnī remarked, “Its chain is sound,” and Shaykh al-Islām said in al-Fatāwā (1/259), “It is an authentic ḥadīth,” and so it is; see also the detailed discussion in al-Fatāwā (2/188–189).

I add: the ḥadīth is likewise cited in al-Mukhtārah (1/93) with these very words. Another wording simply has “You have done right” without the phrase “according to the Sunnah”; this is the preserved version.

He ﷺ would wipe over the upper surface of the leather socks, and any act of wiping fulfils the requirement.
The preferred course for each person corresponds to what he is wearing: whoever has leather socks on should wipe over them.