TLDR: charge to 100% SOC with a timer set to departure time. SOC is State Of Charge
Charging to 100% causes faster "calendar loss", which is time driven. The longer at 100%, the more the loss. (Also high temperature)
So charge to 100% using a timer set for departure time, then drive the car. It will spend very little time at 100%. Especially true in winter, which is when likely more charge will be needed. Low temperatures slow calendar loss. As the LEAF doesn't allow for a lower target SOC, this is easier as well to implement.
Discharging to low SOC increases the rate of "cycling loss", which isn't time driven, at least until you go below 0% real SOC, which the car will not let you get to as the car shuts down at the lower margin (10%? 12% Something like that. I forget). Cycling loss goes up rapidly with lower SOCs.
Also the pilot's rule comes into play... you can never have too much runway in front of you or altitude above terrain or ... meaning for EVs more margin to get home, or more range left after getting home for some necessary trip.
A full answer would need to include exactly how low of SOC the car goes, as cycling loss increases rapidly with lower SOCs, how long and how hot it is at 100% SOC, and more. But it's very clear that battery life will be better with 90%-11% than with 80%-1%, and still better with 100%-21%, as long as you charge right before departure.