Thanks to everyone sharing their end of lease purchase experience. Great info.
I was curious about incentives here (IN) and contacted the dealer we bought the car from. I talked to the salesman who leased us the car in '15 (36 months). He was pretty clueless and said to contact Nissan. I went online to NMAC site and logged in and had a chat with Nissan rep. who said to contact dealer finance, who "take care of incentives now." Talked to dealer finance person and he told me the payoff, which I already knew from NMAC website, and said any incentives are between Nissan and me. WOW.
Looking at current ave. wholesale values for used 3 and 2 year old Nissan Leaf S models, I get $5,425 for '14 and $6,850 for '15, assuming about 8K miles per year. Anecdotally, a friend of ours recently purchased a '15 Leaf off 2 yr. lease (24K miles) with quick charge for $9K retail.
Our payoff is app. $14.7K and residual is $11.6K. I would have to be offered at least $7K to make it worthwhile today, based on the increasing depreciation rate between 2 and 3 year old Leaf models.
If no offer comes to us from the dealer, or is shown on the NMAC website's payoff amount before April '18, I will make an offer to purchase the Leaf for ave. wholesale value before turning it in. It must cost Nissan at least $500 in fees to both transport the car to auction and sell it for wholesale value.
We really like the car, but can just as well buy a used one for $6K-$8K next year if Nissan won't budge.