David Noland:

While today’s Tesla Model S electric car may look just the same as the first one that rolled off the line two years ago, it’s had quite a few hardware updates under the surface.
 But from a Tesla owner’s point of view, the car has been improved far more by numerous updates to its computer software than by a handful of hardware changes — many of which can’t be retrofitted.
 That’s because all owners of a Tesla Model S car get those software upgrades automatically, over the air — for free.
 Try doing that with your new wiper-blade defroster.
 Virtually every aspect of Model S operation, from the climate control system to the suspension, is controlled by software. “A computer on wheels,” some have called it.
 That software, of course, can be updated. The Model S is unique among cars in that it can be reprogrammed remotely from the factory over its 3G or WiFi network. Since the Model S first hit the streets in June 2012, there have been a number of major software updates — on average, one every few months.