I think it depends! More extreme introverts probably need several days (my spouse) while more introvert-leaning folks (like myself--who can be an extrovert around her more introverted friends but more introvert around extroverted friends) only needs a few hours to a day or two.

The best formula I saw was: Two hours alone time for every hour of socialising. That sounds about right to me! And the OP is right: sleep doesn’t recharge us; it just stops the clock, while we’re unconscious!

Haha ooh that's a good one. Yeah, if I see a friend once a week, I'm good. Sometimes I have to go on work trips where I am peopleing daily for 3-4 days at a time and then I'm good for a month.😆

Ditto!