If a muslim grows old, do they have to dye their hair?

[yragnitup]

More evidence from Islamic sources;

Narrated Nafi`:
 
Ibn `Umar said, The Prophet (ﷺ) said, 'Do the opposite of what the pagans do. Keep the beards and cut the moustaches short.' Whenever Ibn `Umar performed the Hajj or `Umra, he used to hold his beard with his hand and cut whatever remained outside his hold.

Reference           : Sahih al-Bukhari 5892 Book of Dress
In-book reference           : Book 77, Hadith 109
USC-MSA web (English) reference           : Vol. 7, Book 72, Hadith 780
  (deprecated numbering scheme)
 
Narrated Ubadah ibn as-Samit:
 
The Messenger of Allah (ﷺ) used to stand up for a funeral until the corpse was placed in the grave. A learned Jew (once) passed him and said: This is how we do. The Prophet (ﷺ) sat down and said: Sit down and act differently from them.
 
Reference           : Sunan Abi Dawud 3176 Book of Funerals (Kitab Al-Jana'iz)
In-book reference           : Book 21, Hadith 88
English translation           : Book 20, Hadith 3170