Tesla announced Saturday it is bringing back free Supercharging on its high-end Model S and Model X.

We've heard that before.

What makes this time different is that the company isn't just offering the incentive on a few cars or in a limited amount. Instead, the company will offer free lifetime Supercharging to all buyers who purchase a Model S or Model X. It doesn't have to be a car in inventory, and no referral fee is needed. The only catch is that it only applies to the original owner of the car and isn't transferable when owners sell the car.

Free, lifetime Supercharging was originally included as standard equipment with every Tesla when charging was rare and buyers were skittish about charging.

Tesla began phasing out free Supercharging at the end of 2016 but has brought it back several times along the way for those with referral codes, as a sales incentive, on certain cars, and for limited amounts, such as 400 kilowatt-hours.

From the beginning, CEO Elon Musk said free Supercharging was designed to give Tesla drivers confidence to take their cars on road trips but was not meant to provide free power for everything a Tesla driver might want to do. In an earnings call last year in the midst of losses for the company, Musk said free Supercharging was "not really sustainable," and said Tesla would end the practice. Still, it was revived a few times as limited offers on all of its models.

Tesla Supercharger station V3, Las Vegas

Tesla Supercharger station V3, Las Vegas

Last month, some owners on the Tesla Motors Club reported that the company was disabling free, unlimited Supercharging on early used cars that previously had lifetime free Supercharging, after Tesla bought them back to resell as certified used cars. 

Now the free, unlimited Supercharging is designed to boost sales of Tesla's older and more expensive models, which have dropped in half as the Model 3 has ramped up to full production.

As the company struggles to generate steady profits even with full production of the Model 3, Tesla is counting on sales of its higher-profit Model S and X to get it there.

Green Car Reports reached out to Tesla for comment on this story, but did not hear back before publication.