I add a little to @alansubie4ever’s post:
Calendar aging is highest initially and lessens further on. But it is very dependent on the SOC and temperature.
Of you use low SOC and st low ambient temps it quite quickly revert to a straight line, virtually horizontal. On the other hand, high SOC and high temps will cause a much higher degradation and the leveling out will not occur, and the slope will be clear.
In the picture below 3.45v = about 20-25% SOC. 3.7V = about 50% SOC. 4.1V = about 90% SOC.
If you are at the left picture, 20-25% SOC and 10-25 degrees you start level of after the first 200 days and after 2 years the degradation will be low, onfly a few percent.
If you are at 4.1V/ 90% and 40 degrees you still are going down rapidly after two years.
View attachment 721847
This picture refers to Panasonic 18650 NCA cells( quite close to Model S and Model 3 for chemistry).
Taken from this very good research report:
https://mediatum.ub.tum.de/doc/1355829/file.pdf
Its way more than 100 pages so its *Battery nerd level reading*
I know which road I would choose, and I have already gone that way, since day one with my M3P