The Leaf batteries still carry an 8 year, 100,000 mile battery warranty, so if they are losing 4 bars in that timeframe you could potentially get a new battery, or at least one not so bad.
Here is when InsideEVs predicts the credits to phase out for each manufacturer:
I think I'll shoot for January when people aren't looking for cars, and have no cash due to the holidays. Also, the new year will instantly make the used cars appear to be 1 year older.