Al-Khaṭīb Al-Baghdādī has mentioned this heading and quotes the following general aḥādīth. He then reports narrations from some of the Salaf about letting elders enter first.
From Ibn ʿAbbās, that the Prophet ﷺ said:
Blessings are with your seniors.
Ibn Ḥibbān et al. Graded ṣaḥīh by Al-Albānī and others. See Al-Ṣaḥīḥah no. 1778.
From Ibn ʿUmar, from Allāh’s Messenger ﷺ that he said:
Jibrīl told me to give precedence to those who are older.
Recorded by Abū Bakr Al-Shāfiʿī in Al-Fawāʾid, and graded authentic by Al-Albānī in Al-Ṣaḥīḥah no. 1555.
It is reported that Mālik b. Mighwal said:
I was once walking with Ṭalḥah b. Muṣarrif when we came to a narrow (entrance). He went in front of me, then said, “If I knew that you were older than me even by a day, I would have never preceded you.”
Al-Khaṭīb, Al-Jāmiʿ li Akhlāq Al-Rāwī #248.
It is reported from Al-Faḍl b. Mūsā that he said:
ʿAbdullāh b. Al-Mubārak and I once came to a bridge, so I said to him, “Go ahead”, and he said, “Go ahead.” So we calculated [the age difference], and it turned out I was two years older than him.
Op. cit. #249.
Al-Khaṭīb mentions after these and other narrations,
“And if the elder gives precedence to someone more knowledgeable than himself, this is allowed, and it is good.”
He then reports that Al-Ḥusayn b. Manṣūr said:
One day, I was with Yaḥyā b. Yaḥyā and Isḥāq (Ibn Rāhuwayh) visiting a sick person. When we all came to the door (next to each other), Isḥāq stepped back and said to Yaḥyā, “Go ahead.” Yaḥyā said to Isḥāq, “You go ahead.” He replied, “O Abū Zakarīyah, you are older than me.” Yaḥyā replied, “Yes, I am older than you, but you are more knowledgeable than me.” So Isḥāq went ahead.
Op. cit. #252.