I would as well. A 2015 would still have a battery and drive unit warranty for another year or so, in case something unexpected happened.
On the other hand, $40k is getting close to the price of a base Model 3 ($46,490), albeit with a considerable wait for delivery, given the backlog of orders (Est. Delivery: Jul 2022). New car with a full warranty. Not as nice as a Model S in my view, but there are those who greatly prefer the 3. And no free Supercharging, although for local driving that is irrelevant and charging is a fairly trivial expense anyway. A new car might be more expensive to register and insure.