If you have a teenager on your auto insurance policy and they have an accident for which they are responsible, your insurance rates are going to climb significantly. If that teenager has another accident, the insurance will be almost unaffordable. Keep in mind that if that teenager is on your insurance even from the beginning, they are considered the primary driver for the most expensive vehicle that you own even though you say they won't be driving it. Teenagers belong on their own insurance policy and you will not be able to get lower rates while they live in your home. Is there more to this, of course there is but these are some things you should be mindful about.