Apple watches are great if you are already in apple ecosystem. But their battery life are disappointing, just like wearOS watches.
It seems that Apple / Android watch OSes are just bad for such tiny devices. What Xiaomi (Amazfit), Garmin and others are doing with battery optimization is way better.
Zepp OS is providing a great SDK documentation, but I went for a Garmin watch thanks to the wide range of apps and widgets already available.
I have a couple of Mi Bands, and they're nice devices. However, they're not watches. They're body monitors with watch functionality patched in, and that's OK.
While the functionality they add-in is intriguing, their low processing power is taxing the mobile phone a lot. I'm in apple ecosystem, and constant communication and process offloading reduces battery life of the phone considerably. Esp, when on the move.
I want a watch primarily. A time keeping device which I can depend and can use for a long time (i.e. years). So returning to a vanilla, bona-fide watch was refreshing and liberating. Having a self-winding, completely mechanical heart inside is also nice.
I use GadgetBridge with my Mi Band. It supports several other brands, is open source, and doesn't noticeably affect battery on the paired phone.
The only annoyance is that a recent update which added support for a device I don't use has caused GadgetBridge to prompt my for a permission that device support needs every time I open the app, and doesn't care that I have no reason to grant that permission. I should make a bug report…
My main battery issue is that the Mi Band's "up to 14 days" (or whatever) is nowhere near enough. I get about 7 days, and I'd prefer "at least 30 days", or...dare I say it?...a few years . (-:
If the Zepplife application is running (even in the background), the band constantly feeds it data about your steps, pulse and whatnot it gets from you, to keep its send queue empty. This wakes the processor a lot, and consumes a lot of battery.
If you're exercising, band establishes and keeps a constant connection about your movement data and pulse. It also gets some information from app (is GPS healthy, etc.).
Both modes keep the phone out of its deep sleep, and halves your daily battery stamina if you have a moderately active day.
Because of that, I actively kill the Zepplife application most of the time if I'm wearing the band that day, unless I'm exercising.
