So many understandable questions about battery usage. The answer: Your battery is monitored by a BMS ( Battery Management System ) this gives you a majority slice of the pie which is not down to 0% nor is it up to 100% of your battery. So the answer with the latest generation of cells and the model 3;s improved design are... Charge the car as fast or as slow as you damn well like as the system will dictate and manage it whatever the road conditions and temperatures are. Set it to that little notch on your app at 90% and keep it topped up just in case or whenever. Why would you close your potential capacity? or fill it right up to limit its regenerative breaking? Its all designed there silky smooth so no worries! No need to even worry about it at all just charge your car as you like at whatever speed you like in harmony with the places you want to drive to, the software and its improvements over time will take care of the battery.