I just recently purchased a used 2015 Leaf.
My first Leafspy reading was on 12/4 AHr 56.815 SOH 91% Hx 86.61
It did go up slightly for a day or so, but has generally been on a steady decline
Today 12/14 AHr 55.890 SOH 90% Hx 84.6.
Last week I mainly charged at L1, then got an L2 EVSE installed...