When you are looking at a used EV, there are apps (along with a dongle you plug into the OBDII port under the dash) that will give you a full diagnostic of the battery. In particular you look at how many times it's been fast-charged. We almost always slow charge it to 80% at home overnight. This will give the battery the maximum lifespan. Of course when we picked out the car, we did take a look at the batteries on several of them before we bought ours. It's a lease return and it was absolutely perfect inside and out. Once you get to the point that the battery is shot, it is possible to replace it. In a Nissan Leaf, the whole bottom of the car can be unbolted and removed. (This is usually done at the dealer service department.) The bottom of the car is one big battery pack. It's a drop in replacement, but a new one will set you back between $6000 and $8000. I have heard that aftermarket rebuilds may be available soon, and it may become a DIY project. I've also seen videos where someone found a wrecked Leaf and stripped the batteries and all the Battery Management System out of the car and reused it to create a homemade EV conversion of a non-electric car. Following this logic, it may be possible to take your own Leaf - with a dead battery pack in it - and take a wrecked Leaf - with a good battery in it - and do a transplant into yours. Or maybe get the replacement battery cells and do a rebuild of yours. I think it's a valid DIY project for an advanced handyman / shade tree mechanic / electronics nerd. I will probably tackle that in 4-5 years when our battery is shot. Overall, I love the silly thing. And if you want a FAST car buy a Tesla. They will blow the doors off of pretty much any production car in the world. This is a 6 passenger sedan and it easily outruns a Bugatti Veyron. I live near a race track and the EVs are disqualified from drag racing against regular gasoline cars. The EVs have their own races.