In my experience of guiding both candidates and firms through the recruitment process over the past 10 years, I feel (barring exceptional circumstances):-
👍 2 interviews is ideal and is expected by most people.
👍3 interviews is pushing it a little, but for more senior level roles can be acceptable.
👎 4 interviews and upwards risks people starting to develop negative feelings and there is an increased risk of people becoming unenthused, or just generally irritated.
If you are bringing people in multiple times before making decisions then you risk losing people to competitors with streamlined and efficient recruitment processes or risk potential candidates not progressing things further with you.