DS is 4. He's in preschool full-time. He has occasional (like twice a month) playdates with a couple of kids from his nursery. He also spends time with his little cousins (once a month) and has occasional playdates with our friends' children. He doesn't seem to have a problem playing nicely, behaves pretty well and is gregarious. I think that's plenty, and at weekends DH and I don't work and always try to get out and about and go swimming or to a museum or park and generally make it all about DS. He is an only child.
It strikes me that all the other children in his preschool have a playdate every other day, and his nursery have suggested he should be having more. The thing is that I work, full-time, (most of the other mums at his nursery don't) and there are only really three hours left in the day before he gets ready for bed. AIBU? Obviously, it's a long time ago since I was 4 years old, but I don't remember this massively engineered 'play dating' scene when I was a kid. It just tended to be playing with whoever was around, family members and such.
For the record, I go out about once a week, either with my DH or a mate for movie night. I am by no means a social animal, so maybe I'm missing something and should be doing more.