TPMS sensors are secured inside the wheels on the other end of the valve stem. They have a battery and transmit the tire pressure reading to the car so that the car can alert you if there is a low tire pressure.
TMPS sensors only need to be changed if their battery is depleted or they malfunction. They do not need to be changed along with tires.
If you get new wheels, TPMS sensors can be moved from one set of wheels to another set.
Conversely, if you want to maintain two separate sets of wheels and tires (for summer tires and winter tires, for example), you will need a second set of TPMS sensors to go inside the other wheel set. The Tesla will recognize the new TPMS sensors after a wheel change within a few miles of driving.
Tesla uses one type of TPMS sensor for VINs less than 50900 (manufactured by Baolong), and a different type of TPMS sensor for VINs 50900 and above (manufactured by Continental). If you need replacements or need a set for s 2nd set of wheels, you will need to get the correct type. In most cases, Tesla has the lowest prices on the TPMS sensors at $50 each.