question #3 Sahih Muslim 467a, Book 4, Hadith 208 : What flexibility does an individual have in the length of their personal prayers compared to leading a group?

The Apostle of Allah (ﷺ) said: When any one of you leads the people in prayer, he should be brief for among them are the young and the aged, the weak and the sick. But when one of you prays by himself, he may (prolong) as he likes.