How long should a smartwatch last on a single charge?

Models such as the Samsung Gear Live, LG G Watch, Moto 360 from Motorola, and ZenWatch from Asus looked like a miniaturized version of a smartphone that doesn't work very well.

Nothing like the sleek, stylish, and capable smartwatches of today. Modern smartwatches are great, but there is one area that remains controversial when it comes to smartwatches. Battery life.

The inverse relation between features and battery life

When the first Apple Watch launched in 2015, things dramatically changed in terms of what a smartwatch was able to do for you. It was the complete experience, done the Apple way. But it only lasted half a day or so…

Coming from conventional watches and having tried some hybrids, I came up with a theory I used to call the "inverse battery life/features relation." It's pretty straightforward and self-explanatory. The more features a smartwatch effectively has, the shorter its battery life is.

This theory holds to this day, and having tested a huge amount of wearables from popular brands such as Samsung, Apple, Fitbit, and Garmin, along with obscure Chinese fitness trackers and smartwatches, I can safely say the inverse relation is still there.

Is battery life that important in smartwatches?

Taking all of the above into account, the answer to this question is no longer a clear cut. I used to bash Apple for the audacity and laziness to keep offering the same "abysmal" 18 hours on a single charge for the Apple Watch generation after generation.

But then I tried using an Apple Watch 8 as a daily driver and quickly found out that one day of battery life is not that different than two days, or even three. I know it sounds a bit out there, but hear me out.

We're creatures of routine. And everything you're doing on a daily basis gets automated pretty quickly. Our brain is a powerful machine that works with patterns and is very efficient with repetitive tasks.

Having to charge the Apple Watch every day, for me personally, was much less taxing than charging my Huawei watch two or three times a week. The randomness and the lack of consistency required additional brainpower.

Playing devil's advocate

I'm not trying to convince you that 18 hours on a single charge is great. Not at all. Coming from conventional watches, I still would prefer a month without thinking about charging this thing on my wrist. And there are smartwatches and hybrid watches that can do that.

I used the Withings ScanWatch for two years, and I was perfectly happy with the 20-day battery life, the lack of a big screen, and the core health tracking that was happening in the background. The key thing is to understand the "inverse relation" I was talking about earlier.

Physics is physics, and there's no free energy. If a smartwatch advertises a week of battery life on a single charge, there are some sacrifices made, for sure. Either the tracking is limited and happening at very long intervals, or the operating system and features are very basic, or the screen is not that bright.

There's no free lunch in physics. Granted, battery technology is evolving and fast, fueled (pun not intended) by the EV revolution. But this energy/features relation will always be there.

So, how long should a smartwatch last on a single charge?

You probably won't be happy about the answer. In a modern reality where ChatGPT and other LLMs are giving you every possible answer to every question and problem, a guy saying "it depends" is not very popular.

For people who are smartwatch power users and do a lot of stuff with their watches, a day on a single charge is kind of justifiable. Leaving your phone home, replying to emails from your watch, listening to music, paying everywhere, and tracking every activity you do — it all adds up.

But if you're okay with your smartwatch just silently tracking your vitals, sleep, and activity; casually checking notifications; setting a timer or two from time to time; and glancing over the time, then you can get days of battery life easily.

Just don't get a smartwatch packed full of features you won't be using and then complain about the short battery life. I used to do it all the time, but now I'm much more aware of my smartwatch needs. 

Some people might find everything in this article extremely obvious, but if it can help other to stop and think about this the next time they're getting a smartwatch, it wasn't written in vain.