If I got one say from 2014 for about $7500, how long should I expect it to last? (In miles and years?)
That depends on where you live.
Like any other modern car, it should go hundreds of thousands of miles if you do the required maintenance.
The battery will degrade over time, and you'll slowly lose range. Nissan is predicting 1 to 3 per year of range loss, so after ten years you could theoretically be down to 70% of the original range.
But it's not as bad as it sounds. Gasoline powered cars are far more mechanically complex, and they sometimes have engine or transmission failures that electric cars appear to be immune to. So instead of spending $3k on a new transmission after 10 years, you might instead expect to pay $3k on a new battery after ten years. Also, electric cars never get cracked radiators, they never need their timing belts adjusted, and the fuel pumps or alternators never go out. Those parts are absent. They just don't have as many moving parts as gasoline cars, so their maintenance costs are projected to be much lower for years and years.
There's a raging debate in the EV community about whether or not battery replacements will ever even happen. Some people believe that EVs will get so cheap, and the technology will progress so quickly, that most people will buy a new one with more range instead of upgrading the battery in an old one, and the old ones will end up in the hands of students or short-commuters who will be thrilled to get a virtually free car that only goes 40 miles on a charge.
