Thanks to Ford Explorers and Firestone, we now have Tire Pressure Monitoring System (TPMS) sensors in each tire of newer cars. Apparently, this was easier than sticking a tire pressure gauge in the glove box of each new car with the owner's manual.
What they don't tell you, and apparently don't tell a lot of the guys who work at tire stores, is that if they break the bead of the tire near the valve stem, they will probably damage/destroy the sensor/sending unit. They also don't tell you that replacing it will probably cost more than the tire. $90 + labor for a Honda Civic, then maybe a trip to the dealer to get the TPMS computer to 'recognize' the new sensor.
Ask me how I know all this . . . .
Four trips to the tire store to fix a nail. One more should do the trick.
Anyway, fair warning if you change your own tires, or if you are getting new tires on a later model car. Apparently, the computer can be taught to recognize extra sensors, in case you have extra wheels that you periodically swap out (like for snow tires).