How to Keep Your Phone and Laptop Battery Healthy

Every phone and laptop runs on a lithium-ion battery, and every one of those batteries slowly wears out over time. The wear is measured in charge cycles — one full cycle equals charging from 0% to 100% once, though it can be spread across several partial charges. Most modern batteries are rated for 500 to 1,000 full cycles before they drop to about 80% of their original capacity, which is when you start to notice shorter battery life.

Three things wear a battery down faster than normal: heat, deep discharges to 0%, and long stretches sitting at 100%. Charging your phone overnight inside a hot car, or leaving a laptop plugged in on a blanket where it traps heat, will age the battery years faster than typical daily use. The sweet spot most experts recommend is keeping the charge between 20% and 80% whenever you can — though this is a goal, not a rule to stress over.

The good news: Apple, Google, and most laptop makers now include smart charging features that do this work for you. Your iPhone learns your schedule and slows the last 20% of charging until you wake up. Pixel phones do the same. MacBooks pause at 80% when plugged in for long periods. You can also check your battery health directly on the device, and when capacity drops below about 80%, it is time to plan for a battery replacement rather than a new device.