That statement is partly true—but the “never charge to 100%” idea is oversimplified and often exaggerated.
What’s actually going on
Most modern devices (phones, laptops, EVs) use lithium-ion batteries. These degrade faster when:
- They stay at very high charge (near 100%) for long periods
- They get too hot
- They’re deeply discharged (near 0%) often
So the concern isn’t hitting 100% occasionally—it’s keeping it there all the time.
A more realistic “best practice”
- Aim for 20%–80% for everyday use if you want to maximize long-term lifespan
- Charging to 100% is fine when you need full battery (travel, long day, etc.)
- Avoid leaving your device plugged in at 100% overnight constantly (occasionally is fine)
- Keep the device cool while charging
Why people say “don’t charge to 100%”
At full charge, the battery is under higher voltage stress, which slightly accelerates chemical wear. Over months/years, that can reduce capacity faster.
But here’s the key point
Manufacturers already build in protections. Many phones and laptops (like those from Apple Inc. or Samsung Electronics) use optimized charging to slow down or pause charging near 100% based on your habits.
Bottom line
Charging to 100% isn’t “foolish”—it’s just not ideal to do all the time. A balanced approach (mostly 20–80%, full charge when needed) is the practical way to extend battery health without overthinking it.
If you tell me your device, I can give more specific charging settings or features to turn on.