There are many routine parental decisions which do not require formal legal authority. They are generally shared by both parents, exercised whenever the children are under their care and supervision. Some examples might be whether to give children whole milk, skim milk or almond milk with their breakfast, (assuming no allergy or other medical issues), what type bike to get the children…a 5 speed or 10 speed bike, or whether to have the children attend to their homework before or after dinner and so on.
Kids and their parents understand there may be different rules in mom’s house compared to dad’s house. However, if one parent has sole legal custody there may be a limit to the latitude they are willing to extend to their co-parent. If one parent chronically allows the children to stay up later when at their house, or allows the children junk food and soft drinks when the other parent is more health conscious, or allows them to watch movies the other parent does not approve of, then trouble lies ahead.