On the downside, you loose the cheap aspect of this watch and the battery life is divided by 7. From 7 years to supposedly a full year.
I buy a f91w because it cost less than 5€ and I don't care to break it or get it stolen.
It's also the only watch I've ever seen with a fully customizable and calibratable pulsometer. I know because I added that feature myself after shopping for watches and not finding a single one that had it. Use it every day at work too.
Where are you getting a genuine F91-W for 5€? A replacement 71604002 band costs me €8!
https://www.casio.com/us/watches/casio/product.ABL-100WE-1A/
With a heart rate monitor it's considerably more expensive.
I tried garmin, apple watch, whoop, and a couple other heart rate trackers recently… they’re very very uncomfortable when coming from a Casio!
It's actually the only watch with all the features I want. It's got a pulsometer built in and I added a calibration feature to let the user set the scale. As far as I know it's the only watch to ever allow this. Use it every day at work.
What's so smart about something that draws many times as much power?
Sure we can strive to do more with less power? It's been decades since this watch was first released.
I don't see any reason things like watches and tracking tags in some couldn't have 10yr life on a coin cell, or like 30 years with an LTO you charge monthly.
Deep sleep currents can be in the nanoseconds, and we only need power for a few milliseconds every minute to transmit an "I'm here" beacon.
Step counts and heart rates are different, but even that can be optimized a lot if you don't need 100% perfect data
