After housing costs and taxes, cars will be one of the most significant expenses over the lives of many people. So it stands to reason that this is a very important area of finance. As with other major decisions in life, there are persistent financial knowledge gaps that need to be filled when it comes to evaluating car costs before deciding on loans or leases. For many people, car purchase decisions are made on one variable: the monthly payment, and that can set you up for significant consequences. The monthly payment is only one factor, and making such an impactful choice based solely on the monthly costs can put your entire financial future at risk.