Should you put your 18 year old son on your car insurance or would it be best for him to get his own policy?

If he resides in your home or at a college dorm.... Depends on his driving experience. If he has a clean record, maintains a high grade point average, it may be beneficial to add him to your policy as a driver to his own vehicle. Most preferred companies offer a substantial discount for good students. All vehicles would also receive a multi-car discount, and he would be covered with the same limits of liability that you carry. If he is a full time student (even thru college years), he is still considered a dependent in the eyes of the law. Therefore, if he is at-fault in an accident, the injured party could still come after you as the parents. Having higher liability limits would be in your best interest under those circumstances. IMHO