I just purchased a Model S 85, but I still have a few questions if anyone can help. Mainly questions about the Battery Life and replacement: 1. Does anyone know how long the Battery Packs are expected to last on average (Miles or Years)? 2.When they run out of juice what then? I have heard they cost like 40 Grand to replace... Can't see putting 40 grand into a car that's 8 years old (as an example). Will the cars be worth much if the battery packs are nearing their age limit? 3. Does Tesla have any type of trade-in program or any plan for cars with half dead battery packs?