I got my new 2013 SL (manufactured 5/2013 ) on 9/30/2013. Lost my first bar 5/2015, second bar 9/2015, third bar 5/2016 and forth bar 8/23/2016 (31,400 miles). First 21 months mostly charged L1/L2 to 80% (home and work). My drive was 55 miles round trip with about 75% highway. As capacity started to go away, I had to charge more often to 100%, however, I tried my best to keep it fully charged as little as possible (extreme Phoenix temperatures).
I wanted to delay replacement even if I was getting at work in the morning with about 12 miles left (from full charge). Just before 3 years, on 9/26 (not charged for third battery check), I was told that the delay in getting a new battery can be 3 months. With that in mind, I asked for the battery to be ordered.
In a month, the capacity loss increased a very few miles (somehow compensated by no AC need in the morning). That was enough to make me accept the replacement, when I was told Friday, 10/28, that my new battery arrived (less than 5 weeks). I dropped my car that afternoon. I got a 9/14 S Leaf as a loaner - similar driving to mine. Saturday afternoon I had back my leaf, with the new battery (AutoNation Nissan Tempe).
I am waiting for more data, but last night I was able to go on highway (15 miles one way, 202 San Tan/I10) both ways, with 61% SOC left (from 100%; in the weekends, driving is 75 - 80 miles/h to keep with the flow). Before, I would have been like 25% at half point - no way to go back on highway.