Sonicare instructs to replace brush after use into charger & states the brush will keep a charge for a week (sounds somewhat conflicting/contradictory to me).

An Amazon user says he: Unplugs his brush between full charges & runs it down to complete discharge. Even though rechargeable battery technology has reached the point where the "memory effect" we used to experience with the old Ni-Cad batteries isn't much of an issue anymore, I think this approach tends to keep the batteries conditioned & gets you a bit more mileage out of your brush handle. The sacrifice you make with this approach is that last brushing as the batteries drain to empty will likely be incomplete. So trot out the old manual standby to finish and then plug in the Sonicare to charge up. With my new Essence, I find I can go about a week this way, brushing twice a day.

Your best advice between the two?