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Tesla brings back unlimited free Supercharging*

That asterisk is mighty important, though.

Charger with Tesla logo at a Supercharger rapid battery charging station for the electric vehicle company Tesla Motors, in the Silicon Valley town of Mountain View, California, August 24, 2016. (Photo by Smith Collection/Gado/Getty Images).
Smith Collection/Gado/Getty Images

One of the coolest perks of owning a Tesla electric vehicle was free, unlimited use of its Supercharger network of 145-kW fast chargers. Then, the program went away. Now, it's back again... sort of.

Tesla will once again offer free, unlimited Supercharger access to Model S and Model X owners, but there are a few catches. Namely, you have to buy a new Tesla with someone else's referral code. If you do that, you get free Supercharger access like owners enjoyed prior to the rules changing -- so long as you're one of the first five using that referral code, since Tesla only lets you hand out free Supercharging five times. If you just buy a new Tesla without a referral code, you'll still be stuck with the pay-per-use Supercharger model.

If you need a referral code, start making friends with other Tesla owners.

Smith Collection/Gado/Getty Images

For buyers who purchased a new Tesla between the end of free Supercharging and its subsequent return, Tesla will retroactively credit your vehicle with free Supercharging. It appears Tesla felt it was the fair thing to do, lest that four-month supply of owners end up getting the shaft compared to, well, just about everyone else.

Originally, Tesla announced that it would shift from free Supercharging to a pay-per-use model starting on January 1, 2017. That date was then pushed back to January 15, 2017. That scheme lived until May 19, 2017, when Tesla announced the return of free Supercharging through its referral program. At the same time, it announced the retroactive application of free Supercharging to all owners who purchased between January 15 and May 19.

This is hardly the first adjustment in Tesla's referral program, and it won't be the last. In the past, benefits involved reducing the price of home charger installation, unique wheels, a new car and even a chance to win an all-expenses paid trip for four to SpaceX headquarters in Los Angeles.