My SL has the option to end charging at a certain hour and the optional option to start charging at a certain hour.
But I'm only using the option to end, not to start. That way, if I do charge to 100% it's just before I get in the car and go, and so the car has sat only a short while at 100%.
Although if I'm sure I won't need 100%, I just switch it to 80%. No harm is done doing that.
The only time I find that the start time to charge option would be necessary is when it's extremely cold. When I set it to end at a certain time and to charge to 100% charging becomes so slow in the cold that the Leaf doesn't start charging soon enough and doesn't charge up to 100% by the time it's supposed to finish. The solution is to set the start time so it starts charging earlier. This doesn't seem to be the case though if I only charge to 80% in the cold.
2013 SL, 40,000 miles, 12 bars.