Both playdates and family time are extremely important to the growth, maturity, and well being of children. That being said how do you balance playdates and family time given the limited time we have for either once our kids are in school? Are there any studies that speak to this?
I would consider why you are organizing play dates. If your children are in school, they have play/social time. Depending on their age, this is less once they are in secondary schools. I think it is important to consider the desired outcome from each interaction. I personally would argue that family time is more important than play dates. I think dinner as a family is essential - every day. I think it is also essential to have family evenings where there are no other events. It becomes tempting as children get older to get them involved in more and more tempting to get your children involved in activities, I would recommend limiting the activities. I notice more and more kids are over scheduled and have minimal time to just be kids and interact with their family. You mention having 4 children, I am one of 5 and we played with each other more often than playing with others and we continue to be close and spend time together.
If you feel that your children need play dates for what ever reason, I would either limit the number per week, or perhaps limit to between school and dinner only. Somehow keep the time to a pre-determined limit and do not let play dates or other things interfere with scheduled family time.
Maybe I can approach the question in a broader sense. In suburban America we have built a community that does not meet our needs. To get anywhere we have to drive. For children, schools are out of walking distance, friends from school can be further than that, and parents don't trust children to bicycle on neighborhood roads. We spend so much time driving that we lose the time we need to live.
In one example I've come across; a child's karate class was less than 1/8 mile away from their home (in a straight line) but to get there his mother had to drive out of their neighborhood, down to the major streets, through 2 red light intersections, do a u-turn, and pull into the karate building's parking lot. A 5 minute walk has been turned into a 12 min drive, each way. For a one hour karate class his mom drives for almost an hour to drop him off and pick him up.
So here's my answer to your question:
We are often tempted to treat our children's time as something to be optimized. We have this feeling that by including the most high value experiences into each day they will grow up to be... what? Instead of optimizing our children’s time, let’s work on optimizing the richness of their environment. Get to know your neighbors and their children. Work to utilize, improve, and expand your neighborhood assets; parks, libraries, schools, community centers, vacant land, front yards, and streets. Plant fruit trees in the front yard, build a garden and recruit neighbor kids to work it with your kids, build bicycle ramps, or close the street for a block party. Get back time for family and friends by making the place you live the place you want to be.
In the long term, the above suggestions will give your children time for unstructured play, exposure to adult role models, and more time with the family. In the short term, I think, focus on time with family and let your children remind you when they want to play with their friends.
I found, by experience, that the best family time is the daily meal time. Set a time that suites everyone's schedule. Stretch the meal to include dessert. Open non-controversial discussions. Give chance to everyone to talk about their day. You want everyone to look forward to it. In short, make it a quality family time.
In addition to the fixed daily time, there are many opportunities for one-on-one interfaces. Examples are driving to and from school, helping with the homework, and discussing personal topics with each individual. Critical and controversial subjects are better handled during one-on-one sessions.
There are also weekly opportunities in the weekend for family activities. This is not regular because it depends on every individual's responsibilities and interest. Family meetings to discuss and make decisions on family matters can be held in the weekend. Hobbies shared between family members brings them together. Also attending children school events are available opportunities.
Playdate is a non-structured time where children spend time together. If there are children of the same age living close by, it is very easy for them to get together. Parents do not have to drive. Arrangement between parents to rotate the visitation is recommended. However, if there is no one close by, children can gather in one home after school. This can be part of carpooling arrangement. Playdates do not have to be every day, although children may like it to be.
In summary, every school day has the following scheduled activities:
The order of the events depends on the circumstances. Some children go to school afternoon, in this case plydates may be before school.
Lives are generally divided into:
The trick is to find natural intersections.
Schedule lessons at the same time as their friends. This way, the kids get to do stuff together and as a bonus, if you are friends with the parents, you get to socialize too. There is a park by swimming lessons so we plan to go a bit early to give the kids a chance to socialize before the lesson. A short playdate (10 mins in the park) then becomes longer.
Also, we have consciously under-programmed our children. This way, we have more family time, especially on weekends. We want to be able to spend time with each child one-on-one. This usually happens during grocery shopping.
Aside from mealtimes, where breakfast is our rallying point (since they are still young), Friday night games help bring us together. Friends are not entirely excluded because "friends are the family you choose".
Hope this helps.