I will be a good test case for your good buy, as I'm entering my second month of 2016 SOUL EV ownership, purchased off-lease with 24k miles. My first modern EV (I have several antiques and converted EVs) was a 2012 Mitsubishi I-MiEV that didn't exceed 20% degradation until after 100,000 miles (with one onboard charger failure, and zero other problems). As my daily i-MiEV use averaged 48 miles on a 62 mile rated vehicle, or 77% discharge, reaching 20% degradation crimped my style, and I replaced the battery with a low mileage collision-salvage unit at 106,000 miles. That i-MiEV is happily running with full range now in spousal use, as a new job brought me a minimum round trip commute of 150 miles four days per week, which is basically eight 80% discharges per week, plus a few shallower discharges, or at least 30,000 miles per year. I fully recharge at work, at home, and DCFC on occasion. I'm optimistic that the SOUL EV will fulfill this mission at least until 100,000 miles, or to 2022, and am keeping an eye open for 30 kWh salvage batteries. I am experimenting with winter heating techniques and am building 4 kWh supplemental battery modules for range extension. (Salvaged LEAF modules to be sacrificially deep cycled daily, reducing the SOUL depth of discharge.)
The key to EV success is to live within your budget and balance the variables. If your cell phone never runs out of charge, you have the requisite qualities, and neither will your EV.
BTW, I hadn't followed the Volt closely, being untrusting of GM quality in 2011 and unwilling to pay the dealers' $12k second sticker, but had read that the VOLT was GM's most reliable vehicle, ever, bar none. Do you think that your declining reliability is typical?