A car that can run on electricity for nearly all of most Americans' daily driving—about 30 to 40 miles—but still has a gas engine for longer trips seems like it should be the ultimate do-everything vehicle. In reality, however, it's highly debatable whether owners actually plug them in. They're also expensive to build, mechanically complicated, and if something goes wrong, you could face the combined repair bills of an electric vehicle and a gas engine. It's not surprising that standard non-plug hybrids vastly outnumber and outsell their plug-in hybrid counterparts in the United States.