4 “You Should Drain Your Battery Completely”
This is a fairly persistent myth, and it’s derived from the days of nickel-cadmium batteries. But draining a lithium-ion battery completely will use up one of its finite charge cycles. In other words, it’ll actually decrease the overall lifespan of your lithium-ion battery.
As with many myths, there’s a grain of truth to this one — although it’s inaccurate for current battery technology. Nickel-cadmium batteries had a “memory,” and it was best practice to let them drain between charges. That’s simply not true for modern-day lithium-ion batteries.