It is healthy, but discharging to 0% isn't and keeping it at 100% isn't either. It is best to plug in at 20% but only charge to 80%. Then every half a year you

It is healthy, but discharging to 0% isn't and keeping it at 100% isn't either. It is best to plug in at 20% but only charge to 80%. Then every half a year you do a full charge to 100% and a full discharge to calibrate the battery management. But sadly that can't be configured on a MacBook.