Right now I would hesitate to buy a used car with 5 years and a 100% of 300 km range but down to 250 km due to battery wear, when I could buy a new car with 500 km range. Owners of first Leafs got hit by already low initial ranges (~120km), so even a 20-30% battery wear have huge impact or car usability. That would change when ranges stops growing (about 700 km, maybe, the same as ICEs?), and used cars have the same range than buying new. 600 km instead of 700 km? Good enough.