Stop Letting the Battery Hit Zero
Lithium-ion cells age fastest when they sit at extreme charge levels, and deep discharge is the worst offender. Every time your phone shuts itself down at 1%, the cell dips below the voltage range it was designed for, which strips capacity you cannot get back. The practical rule is to plug in when you hit 20% and unplug around 80% if you can manage it. iPhones have Optimized Battery Charging, and Android devices ship with similar limits, but they only help if you keep the setting enabled.
If your laptop regularly dies on you mid-meeting, the battery is already degraded, not defective. Calibrating once a month, where you charge to 100% and let it drain to 5%, is fine for keeping the charge gauge accurate. Doing it weekly is just extra wear for no benefit.
Heat and Cheap Chargers Do More Damage Than Charging Itself
Heat is the silent killer of lithium batteries. Leaving a phone in direct sunlight on the car dashboard, or gaming while it charges in a case that traps warmth, pushes cell temperature past the 35°C sweet spot and accelerates degradation permanently. If the device feels hot to the touch while charging, take the case off and set it on a hard surface. Never charge under a pillow or a blanket, because that combination is how batteries swell and occasionally catch fire.
Chargers matter more than most people think. A $5 unbranded adapter from a gas station may deliver unstable voltage that the phone's charging circuit has to correct, which runs hot and stresses the cell. Stick to the adapter that came in the box, or a certified replacement from a reputable brand, and avoid overnight charging on fast chargers. The 45-watt brick that refills a phone in 30 minutes is convenient, but slow 10-watt charging overnight keeps the battery cooler and lasts years longer.
Store and Use Devices the Way the Chemistry Wants
Storing a device at 100% is a mistake people make when they pack away a spare laptop or tablet for months. A full charge at rest stresses the electrolyte, and a dead battery damages itself through self-discharge. The sweet spot for long-term storage is between 40% and 60% charge, in a cool, dry place. Check the device every few months and top it up if it has dropped below 40%.
Using a device while it charges is not inherently harmful, despite what the forum posts say. The battery management system routes power around the cell when it can, so light use like browsing or video is fine. What hurts is heavy load at the same time as fast charging, because the heat from both adds up. If you must game or render video while plugged in, drop the charger to a lower wattage first. A battery that reaches 80% at 25°C will outlast one that lives its life at 40°C, and those habits cost you nothing.