I recently purchased a 2012 Ford Focus Electric in September 2018, specifically to use for commuting 40 miles a day. I am confident that a 2012 -2016 with an estimated EPA range of 76 miles with Level 1(L1) and Level 2(L2) would meet your daily commuting needs with a healthy battery. I'm confident that a 2017-2018 with an EPA range of 115miles with L1, L2 and Level 3 charging would more than well meet your needs as well.
I purchased my car in the Fall and had access to L1 charging at work, as I when I purchased it from the prior owner, they informed me that for our winter's that they recommended that I charge at work to cover any range loss due to the cold. This had been my primary concern prior to purchasing the vehicle as, I wanted to be range confident in the worst of conditions(e.g stuck on the highway for several hours in a winter storm in under 20F weather). My experience in the Fall and Winter have been great commuting because of that advice and as of late winter/early spring, I've increased my habit from simply commuting to using my car during work to get allow me to get between sites minimally 10 miles away, but as far as 20 miles away. However, at these sites, I do have access charge via L1 when I will be at one site for 3+ hours and L2 if less than 3 hours, which will ensure that I have enough range for the commute back home.
Thus, my recommendation is for the 2017-2018, if you do not have any plans to charge at work, as I think this will cover your full round-trip needs. I recommend the 2012-2016, if you have the option to charge at/near work, to provide a buffer if you need. One of my habits in driving after I purchased my car, was I primarily started driving on the streets versus the highway because I enjoyed the regenerative breaking on my commute, which improved my range confidence. The highway speeds in my area is 55 miles for 80% of my commute and the last 20% is 65. On the street, it ranged between 35-45 and I generally saw complete better accuracy to the EPA estimate.
In terms of maintenance, I've only had an alignment, wheel balancing when putting on a set of new all season tires, which I will rotate with winter tires and the cabin air filter. The car presently has 62,000 miles on it and I purchased it with 48,000, so I've driven it 14,000. I estimated 10400 miles initially for work(40 miles a day x 261 working days). Accounting for the weekends(40 miles a day x 104), which would add another 4160 miles, I would just be 3,440 less than the 18K that you anticipate.
In terms of routine maintenance, your local mechanic should be able to do the general service work you need. You can use Ford site(https://www.ford.com/dealerships/
) and choose Certified Electric Vehicle Repair, to see if there is a dealer close to you for any specific EV repairs. I have at least two in my area, so you may be able to find one close to you. I invested in getting a subscription of alldatadiy.com, as I had already had a subscription with my prior vehicle. I have viewed the wealth of knowledge in this forum as well and if I need can purchase the service manual from Helm Inc(https://www.helminc.com/helm/homepage.a ... uckgo.com/
). I was able to purchase a wiring manual for under $15 on eBay, as I was interested in knowing the differences betewen the 2012 and 2017 wiring for the charge port and battery wiring.
As I've had a desire to do longer distance driving, I had been interested in some of the projects on the forum pertaining to fast charging for my model year. During this time, the parts department priced the replacement battery for a Focus a $22,000 and at the time, I found two 2017 Focus within 500 miles of my area for $17,000, I could have purchased a newer model for less than the battery.
Lastly, I have not run any test on battery degradation. 19.50Kwh is the maximum amount of energy that was put into the battery for my longest trip, which was 53.9 miles on a 30F - 40F winter day using defrost and heat in December 2018.