I agree tennis is very mentally taxing and at the beginning taking breaks over the winter is a good thing. It also depends on how seriously you take your tennis. If your just doing it for fun and your kid likes to play other sports taking the winter off seems to be the way to go(as it is very expensive.) ON the other hand if your child is serious you will need to play indoors to keep up with the kids who are. It will be frustrating to come back and have seen everybody else improve while you didn't. So it just depends on your level of seriousness imo.