It's all about managing risk, isn't it? Car broke down? Rent one, call a friend, take a bus... I, personally, pay for a spare year round on the off chance that something comes up and I need it. It's like buying Snowmobiles... They are fun when there is snow on the ground but if there isn't, you are just paying for, maintaining, insuring something unecessarily. The second car isn't a necessity but it is nice to have. When my wife's Explorer got a little too close to the stopped vehicle in front of her, it was down for repairs for a month. It took USAA about 30 minutes to secure a replacement loaner for her (same year Explorer even but with better options).