A battery failure would do some serious damage to your bank account.
Yes, to repair the car, that might cost a bit too much to be reasonable. But the repair price is NOT my loss, as long as it's not repaired. The loss has already occured, as it's de depreciation of the car I drove.
Used prices here show me the following:
My car from 2015 lost about 1/8 of its value every year, slightly more. Now at 5 1/2 to 6 years old, it is down to 1/4 of the original price. This was not linearly, of course, for the past.
I expect it to be down to 1/8 of the purchase price after the 8 years (not reaching 0, as it would, when continuing to lose value linearly).
The risk in driving it longer than 8 years, without a warranty, is that remaining 1/8. Well, 1/8 when it dies the first day after the warranty expires. Which is not very likely. So, to adjust for that, the risk is in fact about 1/8 minus the value I get from driving it. The value of driving it is, of course, much less than the annual price drop from a then new car.
This math is right for a potential second owner also, if I sell the car for 1/4 (now) to 1/8 (or slightly more when before) 8 years. This of course means I am realistic enough to face the loss in driving sich an expensive vehicule, which already occured. And for a potential buyer, it's fair if he gets a car out of warranty for about the real value. NOT what potential sellers dream of.
My situation would be as follows:
- change to a new Tesla, which will lose about 1/8 of its price every year. More in the first year, to be honest.
- keep the one without a warranty, an potentially lose the same 1/8, with the chance to drive it 2-3 more years. Or longer.
(other effect that might play a role, that I left out here:
- a car with a defective battery might be worth more than zero (spare parts, not to be repared)
- driving a new one means being able to use the new tech which the old one hasn't got on board.
