It depends - lol. We tend to socialize intentionally less in the summer and with the exception of soccer we have no planned/scheduled regular activities
During the school season we have classes and sports programs (where the primary focus isn't socializing but it happens anyway) , semi structured activities (field trips, volunteering, etc) where socializing is one of the main goals and playdates/get togethers where it's mostly about socializing.
I try to limit my kids to 2 sports/lessons each per school season in addition to the stuff we do as a family. We're less likely to socialize when we are busy with programs and semi structured stuff.
Our year next year is shaping up like this:
Monday: science or art co-op (all kids) , skating lessons followed by a free skate with friends (all kids), and a French co-op (all kids). This is a heavy day and I am rethinking some of it.
Tuesday and Wednesday are home days and I'll try not to schedule anything for these days in general. We may go out but it won't be an intentional "socialization event" -

- maybe a hike or a museum trip or to the grocery store.
Thursday: French preschool for my youngest in the morning, older kids at home for the am, dance/gymnastics and indoor soccer (various kids at various things in the late afternoon/evening) We'll probably slot playdates in on Thursday afternoon.
Friday: our enrichment program for the whole family (alternates btn nature centre, musuem field trip, community volunteering and general fieldtrips with the same group of 25 kids) followed in most cases by a lunch or snack together as a group.
Saturday - Hockey for ds9.
Also thrown into the mix is a regular weekly visit with grandparents and a monthly co-op family gathering/potluck or outing with 10 families.
Frankly it exhausts me to read it written out like that.

With 4 kids it often feels like most of us don't need any more socializing than what happens in our family.
ETA that almost all of these activities happen with families my kids consider to be their best friends and many of the programs are either relaxed or have a time for play built into them.