I've got a 2014 LT1 that I bought two years ago with 10,000 on the clock. I replaced the original front tires at roughly 20,000 and then the next year with about 38,000, I replaced all four after I apparently destroyed one of the rear tires with something on the road.
Made a trip last weekend to pickup a computer at a store that the round trip with no charging was within a dozen miles with no recharge, had a little diversion and returned home with 2 miles of range left and usage of 13.4 Kw with 99 percent of the power used.
Notable about this particular spark EV is that it was first registered in Michigan in February 2013 meaning it was an early production unit (the VIN ends in 00067 if memory serves) tagged by GM in Detroit so it is one of the oldest batteries. And as I think about it, I seem to be losing about a KW of storage a year of usage.
Winter-time range varied from the high 50's mostly but on the milder days low 60's this year whereas last year range was always in the mid-60 mile range as winters are relatively mild in Georgia.
I did decide to try using cheap-o tires bought online from walmart for right at $40/tire as, at least on the fronts I'm only getting about 15000 miles (rear tires were replaced with cheepo's too as one had succumbed to a road hazard.)
BTW: 2014's battery warranty is supposed to be invokable when you lose 35% of the batteries capacity. I just never quite grasped what that amounts to in Kwh storage ... Also the warranty is good through next January.
Funny thing I'll add. I'm not sure I want to return to the local dealership as the last time I took the vehicle in (only chevy store service needed) to refill the coolant level in the battery maintenance system, (it wouldn't accept a level 2 charge) then sent it back with some rather odd off-hours charging schedule that would mean five minutes of charging at 3 am. When it wouldn't take a charge I had the sense at the time to check and found the software setting for delayed charging. I'm pretty sure the dealership (they used to be an advertiser of mine) was jerking my chain and figured the tech would be too much for a 69 year old man
Anyway, the question that spurred that was who at GM would I contact (mychevy has no listed service outlet and obviously I'm in GA, not CA (but remember this car was first registered in MI. so it entered the distribution system as something other than a new car delivery.)