Most small electronics that have built-in, non (user) replaceable batteries, use lithium ion battery chemistry. These batteries are lightweight, rarely if ever leak, and are energy dense, which makes them ideal for small devices.

Time and experience has shown that lithium ion cells will have a longer service lifetime if we don't continually charge them to 100%, choosing instead charging to 80%.

Most laptops and phones today include user selectable charging options that limit the charge to some preset amount. 80% seems to be the sweet spot. That's not to say that you can't charge to 100%, even repeatedly so, if you are going to be away from a charger all day.

But for many of us, plugging in periodically during the day is entirely possible and convenient, like in the car or at our desks. So why not plug in when you can? If you can do that, you could pretty easily get away with setting an 80% charge limit.

e.g. I have wireless charging magnetic phone mounts on my desk, nightstand, and in the car. So my phone is pretty much always at 80%. I put the phone on the mount and it starts charging. No cables to fuss with.

Why is charging to 100% suboptimal?

Without getting into battery physics, it has to do with cell chemistry. Charging to 100% increases peak voltage and places additional stress on internal connections and electrodes. There's no headroom or slack remaining.

Think of this human analogy -- something we've all done before: Sit for dinner and eat so much food that we couldn't possibly eat another bite or we might barf. Yes, you know how that feels, like at every Thanksgiving meal ever.

You also don't want to let the phone get too low before looking to charge. I recommend not letting it dip below 10%. This, too, stresses battery cell chemistry. Thus, maintaining charge between 10 to 80% is ideal.

When was the max charge feature introduced?

For laptops, selectable charge limits appeared as early as the mid 2010s on some models but rollout was spotty and uneven. Today it's pretty common across laptop brands though not completely universal. But it's not enabled by default. You must select that feature.

Apple and Android phones were both much later to the party and did not get true, user-selectable max charge settings until very recently. In the last year or maybe two (as of this writing, early 2026). As with laptops, you must select this feature. It's not automatic.

How to access this feature?

Different devices have different ways for setting a max charge level. You may need to Google the steps for your device. But, generally, you'll go to the battery or power settings and poke around until you find it. Set it and forget it.

This article really can't give you step-by-step instructions due to there being a wide variety of devices, but it can make you aware that 80% is a thing and that you might want to look into it. So now you know!

Another possibility for having extra power on hand is to buy a portable power bank. Some of them are quite small and lightweight. You might decide that's a good way to have extra power available when you're away from power mains and still have your phone or tablet max charge set to 80%.

In other words, having a power bank might make you less nervous about not charging to 100%. It's up to you.

When battery longevity meaningfully declines

If you bought your phone new and if the battery doesn't fail prematurely, you'll probably be ready to upgrade by the time battery capacity noticeably diminishes, which, in general, is between 3 to 5 years. You could choose to have the battery replaced but it's probably not worth it by then.

Laptops can be relevant for much longer, upward 6-8 years, so replacing a failing laptop battery is something more people may consider.

Replaceable AA and AAA batteries

Some devices, like computer mice, TV remotes, and other small devices might have user-replaceable AA or AAA "penlight" batteries. I strongly recommend using Energizer Ultimate Lithium batteries -- not alkaline batteries.

Why?

Alkaline batteries are prone to leakage, leaving corrosion and gunk inside the device's battery compartment, and possibly damaging the device itself.

Energizer Ultimate Lithium batteries, on the other hand, rarely, if ever, leak. Yes, they do cost more. If the gadget is a cheap toy, then might not be worth it.

You might also consider using Panasonic Eneloop rechargeable AA and AAA cells for devices that rapidly consume batteries. You'll save money in the long run and not contribute to landfill waste.