I picked up a used 2012 about 3 years ago. It had around 25K miles on it. At that age, the battery had lost close to 25% of it's capacity, reducing the "regular driving" range proportionally. If that is the original battery, it's likely lost close to 1/3 of the original range by now based on mileage and time.
Not that somehow makes it unusable, you just have to be aware that it's likely a 50 mile car now.
If you can do an extended test drive, it's possible to measure the amount of remaining capacity using the trip meter before you buy it. Do your best to get it topped up, reset one of the trip meters and run it down driving it around. If you can get it on the highway, shouldn't take to long to get it down to zero. Also keep in mind that when it's at 0% there's actually 1kWh left to use and it will limit your peak power output, so you can still be a couple miles from home and make it back. At that point you can park and run the heater or AC to keep drawing the battery down until the green "ready to drive" icon shuts off and you'll hear the HV battery contactors open. At that point you're effectively at zero and the kWh reading on the trip meter will reflect the total usable capacity left in the battery.
I believe the brand new Energy to Empty was 18kWh plus that 1kWh reserve. I'd wager this one is closer to 12kWh usable by now. Just something to keep in mind so you're not caught by surprise. Even with a 65 mile usable range I was able to put 2,000 miles on it in a month - I was just charging more frequently to do it and with a bit less efficiency.
I love mine and so long as it has enough range to be useful for you, I'd say it's a great deal. I did end up needing a pack swap like many other older ones, so it's not a given that what's in this one is original, could be much newer - though if it hasn't yet been replaced it's getting pretty close to the battery warranty cutoff.
2012 Candy Blue FFE with a 33.5kWh battery pack