Any time I have a chance to charge to 100% (don’t have charger at my parking space) and I expect the car to be down to 80% by the time i am home. So for example, lets say I’m away from home, stopping for dinner at a supercharger, and know that it takes 20% charge to get home. That’s when I’d charge to 100%. From what I understand there’s no problem with charging to 100% but there is a problem with letting it sit at 100%.