Future Planning....

I'm going to look at a 2018 with 102,000 miles this weekend. Fist time for Hybrid or EV. Just trying to think of expense planning, what's the worse case scenario? The haters talk about battery cost, how long do they typically last? and I've heard they can be rebuilt? How realistic of the issue of buying a car that's no longer supported, hard to find parts? I would love to reap the rewards of fuel savings and live in an area with pretty decent electric rates, just trying to think it all through.