7 or 8 years is an extremely long time to finance a car. Do we know how much battery life will be left after 8 years?
That is the warranty period so I don't think you'll have any trouble:
https://www.tesla.com/blog/infinite-mile-warranty
> the 85 kWh Model S, our most popular model by far, now has an 8 year, infinite mile warranty on both the battery pack and drive unit. There is also no limit on the number of owners during the warranty period.