I saw ‘Uthman b. ‘Affan performing ablution. He then narrated the same tradition. In this version there is no mention of rinsing the mouth and snuffing up water. This traditions adds : “He wiped his head three times. He then washed his feet three times. He then said : I saw the Messenger of Allah (ﷺ) performing ablution in like manner. He (the Prophet) said: He who performs ablution less than this, it is sufficient for him. 73 The narrator did not mention prayer (in this version).
Sunan Abi Dawud Book 1, Hadith 107
← Previous Hadith I saw ‘ Uthman’ b. ‘Affan while he performed ablution. He poured water over his hands three times and then washed them. He then rinsed his mouth and then cleansed his nose with water (three times). He then washed his right arm up to the elbow three times, then washed his left arm in a similar manner; then wiped his head; then washed his right foot three times, then washed his left foot in a similar manner, and then said : I saw the Messenger of Allah (ﷺ) performing ablution like this ablution of mine. Then he (the Prophet) said: He who performs ablution like this ablution of mine and then offered two rakhahs of prayer without allowing his thoughts to be distracted, Allah will pardon all his past sins.

Sunan Abi Dawud Book 1, Hadith 106 Next Hadith → Ibn Abi Mulaikah was asked about ablution. He said : I saw ‘Uthman b. ‘Affan who was asked about ablution. He called for water. A vessel was then brought to him. He inclined it towords his right hand (poured water upon it). He then put it in the water three times, and washed his face three times. He then put his hand in the water and took it out; then he wiped his head and ears, in and out only once. He then washed his feet, and said : Where are those who asked me to perform ablution? I saw the Messenger of Allah (ﷺ) performing ablution like that.

Abu Dawud said : All the sound traditions narrated by ‘ Uthman indicated that the head is to be wiped once, because they mentioned (the washing of each part in) ablution three times. In their versions of tradition they mentioned the wordings: “he wiped his head.” In this case they did not mention any number as they did in other cases.

Sunan Abi Dawud Book 1, Hadith 108