question #3 Sahih Muslim 731a, Book 6, Hadith 134 : How did the Prophet (ﷺ) balance between sitting and standing during his night prayers?

I did not see the Messenger of Allah (ﷺ) reciting (the Qur’an) in the night prayer in a sitting position, till he grew old and then he recited (it) in a sitting position, but when thirty or forty verses were left out of the Surah, he would then stand up, recite them and then bowed.