Tesla announced in November that it would stop offering new Model S and Model X owners free unlimited Supercharger access. While that change is still going to occur, it’s pushing back the implementation date. The offer was originally going to expire on January 1, but now buyers have until January 15.
If you buy one of the vehicles prior to that date, you’ll continue to receive unlimited (within reason) access to the Supercharger network.
Customers who purchase a Tesla vehicle after January 15 will get 400 kWh of free charging credits each year. They’ll face a “small fee” if they use more than those credits.