Thanks for this. Does this refer to charging before a trip or leaving a car sitting? In other words, if I charge to 80% before a road trip, or when I'm going to be out running errands all day, will that quicken my degradation?
The rule is pretty simple, more degradation rate above 55% (about 2x) than below 55%. This is calendar aging and depends on time. All 24 hours count, driving, charging, sitting. Yes the time spent above 55% will degrade it more (especially in the heat another major factor), but the details of the charging cycle don't matter too much for this. This motivates the idea to charge late rather than early, so that the time spent sitting (majority of time) is at a lower charge level. It's time prorated so a small amount of time over 55% means a smaller contribution to degradation.
I charge higher than 55% occasionally when I know I'll make a longer trip, and don't worry about it. Maybe 20 days per year at most.