The battery is really the known unknown here. The leaf battery has a 96 mo, 100k mile warranty for at least 80% capacity, so you shouldn't have to sweat it for the first 8 years at 12k mi/year. A replacement is $5.5k, but plenty of other hacks available (play the replace the weakest cells game, or carry extra cells somewhere to augment the pack). They already have
eniger kits to add 40 miles to a leaf (and a diy version can't be too horrible). And really that is the only thing likely to go south (where south is slightly reduced range), and it is way more reliable than an ICE (manufacturers routinely give an extra 3 years and 40k miles on electric drivetrain parts). So having actually thought about it, I'm not at all concerned, this thing should just keep going and going (knock on wood).