My BIL and SIL have been examples of the cohousing approach, for health and economic reasons: housing BIL's parents, SIL's mother (until she passed of cancer- having her there was a godsend from a care perspective), 2 grown children with developmental disabilities and another SIL. A pretty small house that is really crowded at times, but they make it work and I don't hear them complain much. I feel guilty because we have a bigger house and just 4 of us.
When I was w*rking full time, I was not big on company after hours since I had so little free time. My attitude has changed a lot and I try to take the time to visit more with family and friends, but I don't think I could handle full-time living together. Too much potential for trouble I think. I do wish our houses were closer though, for more spur-of-the-moment activities.