I think there's wide variability in the social needs of humans as a function of past experience, genetics, and age.
But I think that 15-20 is about right for a sustainable group generally as long as you've got the right skills in the mix. Fewer than that and a few lazy people and things fall apart. More than that and you start forming cliques.
Once you get into multi-generational it gets interesting. I know at least one place like this where a bunch of families sort of just went in on some land and then coparent as a community.
But I think that 15-20 is about right for a sustainable group generally as long as you've got the right skills in the mix. Fewer than that and a few lazy people and things fall apart. More than that and you start forming cliques.
Once you get into multi-generational it gets interesting. I know at least one place like this where a bunch of families sort of just went in on some land and then coparent as a community.