Mostly an auditory processing fatigue thing for me. If I can isolate and listen to music for a while, I can bounce back.

I'm not sure. Mostly because I've never reached to a stage where i actually crave being around other people and in day to day activities. I have to be around other people, so recovering is kinda irrelevant.

Deoends on if I like the people.

Depends, if there is enough socializing and activity sometimes I needs days to recover.

Depends on what happens but half a day at the shortest. If a meltdown happened, like 3-5 days.

Depends on the people. I never really need to recover from being around my brother, for example. OTOH, my mom is exhausting to be around for more than 30 minutes. I like having at least a night to recover after visiting for a day. I don't do external silence tho.

Sometimes I have to take a break while I’m with people!

Too long. Feels like having run a marathon. Luckily i can take my time as long as I want, wifey is the same. We both need quiet after some people-action 😁 She like people though, so it's even harder for her.

until time ends

When I am completely peopled out, usually takes me a full day.