How many friends do you think it would take before your introversion/extroversion should be questioned?
An introvert doesn't want to be alone 100% of the time. It follows that an extrovert wouldn't want to be surrounded by people 100% of the time.
How much alone time does an extrovert want on average?
I'm not sure about how
many friends, but I think the cycle in which you see them is important.
Witnessing the patterns in my highly extroverted father (ENTJ), my childhood best friend (ESTP), close friend from college (ENFP) and graduate school (ENTJ) I have seen quite a diversity in the number of friends, but a similar pattern in how they interact and how much quality and alone time they need.
My dad and graduate school buddy (ENTJ) like to get to know many different people and have something to do 4 or 5 nights per week with them. However, they, like most introverts I know, have only three or four people in whom they confide.
My best friend from childhood (ESTP) is not very friendly, appears like a lone wolf to 99 percent of people, but likes to be around his four close friends VERY often. When we lived in the same town, he would come by my house about six nights per week. We would smoke cigarettes (I quit years ago) and he would talk while I would nod my head or question his logic. Lots of fun really. But in public you wouldn't guess that he talked much at all.
My close friend from college (ENFP) is one of those people who will talk to ANYONE. He is very agreeable and has lots of friends. He is a middle school history teacher and I wouldn't be surprised if he is voted teacher of the year at some point because he is so good with kids and he has a quick, able mind. During college it wasn't unusual for him to bring someone to our apartment 5 or 6 nights per week. Holy hell, it bugged the shit out of me. He and his friends used to call me The Hermit because I would walk downstairs (bedrooms upstairs), walk past his friends or girlfriends in my boxers, grab food, and walk past them again never acknowledging their presence.
He used to confide in many people, but as he has matured it appears to me that he has dwindled his very close friends from 15 or so to about 8 (an estimate).
Conclusion:
How many friends do you think it would take before your introversion/extroversion should be questioned?
I don't think you can assess a persons introversion or extroversion purely by how many friends they have, but in how much
time they spend with them and with how many in whom they confide who they think and feel themselves to be. If they are spending 5 nights per week with four or five different people, then that is a decent indicator of extroversion imo.
How much alone time does an extrovert want on average?
One or two nights per week. Or a few hours per day.