Car insurance works differently than health insurance. There is no magical age or employment status that drives your children's ability to 'be on' your auto policy.
If your child owns their own vehicle, then really that becomes the point at which they should have their own policy. To complicate things, if they still live with you then they must be listed as a driver on your policy as well (you would also have to be listed as a driver on their policy).
If they have moved out of the nest and do not have a vehicle, they can still be listed as a driver if they are regularly furnished one of your vehicles. This may help them when the time comes that they are purchasing their own policy in showing continuous coverage.
So in summation, if they are living in your household or regularly furnished a vehicle then they must be listed as a driver. If they own their own vehicle then they should have their own policy. Speak with your broker to make sure this is the case in your state.
If your child owns their own vehicle, then really that becomes the point at which they should have their own policy. To complicate things, if they still live with you then they must be listed as a driver on your policy as well (you would also have to be listed as a driver on their policy).
If they have moved out of the nest and do not have a vehicle, they can still be listed as a driver if they are regularly furnished one of your vehicles. This may help them when the time comes that they are purchasing their own policy in showing continuous coverage.
So in summation, if they are living in your household or regularly furnished a vehicle then they must be listed as a driver. If they own their own vehicle then they should have their own policy. Speak with your broker to make sure this is the case in your state.