A teacher "Call me by my first name otherwise I feel old" What is more important, students right or his issue?

If a teacher insists that students call him by his first name and some students don’t want to, whose right comes first, the students need to call him by his last name “Mr. ..” or his wish/“need” to be called by his first? What if the students want to maintain a certain amount of formality that goes with an authority figure (or they don’t like the him/her) but they don’t want annoy the teacher. That is just one example really. Employer employee is another example. In your region what happens re. this kind of thing? Is it upto the person who is being addressed or the addreser?