Is your car on finance? If it is, definitely a good option, if not, then not so much. If you have never had an accident in all you driving history, then you are less probable to have one in the future. If you have had a few, then your driving may be contributing to it, and you would be more probable to have another. Low risk, I would not bother buying shortfall insurance, High Risk, I would certainly be considering it and definitely with finance.