Same as Russk, mine is always plugged in.
Unless the car is driven daily the Batt will suffer from infrequent drives, but the tender keeps the battery from deterioration.
2016 Aventador Roadster: Grigio Iris
2017 Huracan Spyder 580-2: Bianco Icarus
2016 MB SLK-350
2015 MB ML-350
2014 Audi R8 V10 Spyder