So as a before reading my commute to work (about 15 or 16 miles one way) uses about 19% SOC.
That's with the Goodyear Eagle RS-A around 50 psi in summer driving.
Since SOC won't go above 93% on this car and it goes into turtle mode around 1.4% Lets say there is a usable range in SOC of about 90%.
90 / 19 = 4.7 trips to or from work on a full charge.
Strictly speaking SOC is a variable unit of energy and wouldn't be sufficient for rigorous testing but the battery degrades at a slow enough rate that the difference in energy contained in 20% one year vs the next won't be much different.
If we wanted to track it in more absolute terms we could do it in GIDs. See
My Nissan Leaf Forum • View topic - What is a "Gid"? for what a GID is.
OK, just in case it matters for later, my current SOC to GIDs is something close to
92.5% SOC = 225 GIDs
80% SOC = 190 GIDs
turtle is assumed to be somewhere around 1.5% = 5 GIDs but I haven't confirmed. I've never driven this car to turtle yet.
actual last trip to work was from 80% SOC / 190 GIDs to 62.2% SOC / 143 GIDs
I haven't saved a screenshot of being charged to 100% since May 28th so my GIDs being 225 at max charge was when the SOH was 92%.
All in all measuring battery capacity on the fly as you drive is an inexact process. You only truly know the exact state of charge at the top and the bottom, any where inbetween and you and the instruments are guessing.