Tesla has updated its Supercharging Network of free fast-charging stations. Customers who purchase Teslas after January 1st, 2017, will be required to pay "a small fee to Supercharge." The fee itself "will be charged incrementally and cost less than the price of filling up a comparable gas car." The Verge reports: Current Tesla owners with Supercharger-equipped cars will be able to use the stations for free for the life of those vehicles, and a Tesla spokesperson tells The Verge that the free charging will transfer to successive owners. Customers who buy Teslas after that January 1st cutoff will be afforded 400 kWh of free Supercharging credits each year, good for about 1,000 miles, according to Tesla. The company says it will release more details about the change later this year, but added that "prices may fluctuate over time and vary regionally based on the cost of electricity." "Our Supercharger Network will never be a profit center," the company wrote in a blog post about the change. Tesla says that, by losing less money on providing free electricity at these stations, that the fees will subsidize the continued expansion of the Supercharger network. The Superchargers allow for a full charge in about 75 minutes or a half charge in about -- much faster than the standard Level 1 or Level 2 chargers found around the U.S. -- and Tesla has built 734 Supercharger stations (with nearly 5,000 chargers) since the network was started in 2012.