If you watch much television these days, you’ve probably noticed the steady stream of ads for extended auto warranties. They tend to follow a familiar pattern. A confident spokesperson—sometimes a recognizable name like Danica Patrick—talks about the rising cost of repairs. Engines fail, transmissions go out, electronics stop working, and when they do, the bill can run into the thousands. The message is clear: protect yourself now, before something goes wrong. It’s a compelling argument. But like most advertising, it leaves out part of the story. Most of these plans cost somewhere in the range of $800 to $1,200 per year, depending on the vehicle and level of coverage. Over time, that adds up quickly. Three years might cost $2,500 to $3,500, and five years…