The school calendar is also personal choice. It is required by Idaho law to have a total of 180 days of school a year, but these may be any 180 days. Some families prefer to follow the public school calendar. Some families choose to hold school year round. Some have three weeks of school followed by one week off all year round.
Some families teach all summer and take winter vacations.
There are many choices. Only you know yourself and your children best. All children are socialized. Your responsibility as a parent is to decide what form of socialization you choose for your children. One popular opinion would have parents believe that children need long periods of interaction with their peers to acquire proper social skills.