while it is ertainly not good idea to intentionaly deep-cycle Lithium based batteried, there is also another good advice: remove battery when you intend to use laptop for long time (more than sy 3 hours) on mains power. Althought lithium-based batteries tend to lose capacity with age, this effect is strongly correlated with temperature and running laptop produces heat that will increase battery's temperature. (this requires wall suply that is able to cover laptop's peak power usage, which is nowadays not always the case)