Having a high policy limit is arguably one of the most important options to consider when getting car insurance. So many people choose the lowest policy limits to save money, but this is a “penny-wise, pound-foolish” situation. If you are ever in a serious car accident and have severe injuries, you will want a high policy limit. Under Insurance Policy (UIM) states that when the policy limit of the at-fault insurance is exhausted (assuming the other driver is at fault), you can supplement additional compensation from your own insurance policy. However, this can be done only if your insurance policy is higher than the at-fault insurance policy. This means, if your medical bills are $50k and the at-fault insurance policy only carries a maximum of $30k, you can go to your insurance policy for over and above $30k if your own policy is over $30k. If your policy is also $30k then you cannot collect a dollar from your own insurance as supplemental coverage. This can have a huge impact in cases of serious injury, where medical bills are high.