That's an amazing battery life these days. Love my Apple Watch, but having to charge it at least once a day, is a chore.

Might take another look at these - given the price, it's not a huge gamble to try it out for a few weeks.

I feel the same about the apple watch. All I use it for is literally tracking steps. I do not care about any other feature. If my watch fails I will just get a casio watch.

I was surprised to see it uses CR2016 batteries and still manages to get two years of advertised battery life.

Apple airtags last maybe a year on a CR2032, from experience.

I mean, airtags are doing radio stuff at a regular cadence. I've noticed they update once every 15 minutes, so they are turning the radio on to do whatever BLE triangulation they need to do 96 times per day. That's milliamps over at least a few milliseconds to wake the radio, do whatever triangulation is needed. It's amazing that they last that long considering what they are doing. I think they are using Nordic NRF54 internally so it's testament to the power efficiency those chips are capable of.

Airtags don't do any triangulation. They just send out a BLE beacon periodically to any iPhone within earshot, and also spend some time listening for new instructions that almost never happen.

They have no idea where they are or what their airtag/BLE neighbors, if present, are doing. They don't grok GNSS or wifi. There's nothing for them to triangulate or trilaterate or tri-anything when they're just sitting there.

So yes: They are indeed pretty tidy about energy consumption. They accomplish this in large part by being very simple in normal operation and leaving the heavier lifting to the world of iPhones with relatively enormous batteries that get recharged ~every day.

I was about to ask that - I somehow doubt it will last 2 years if you keep the step counter + Bluetooth on.

Bluetooth stays on only for three minutes and then turns itself off once you're done syncing stuff. I have had one for nearly two years now (ABL-100WE). Absolutely love it.

OK, but what about the step counter. Can it really last 2 years with the step counter continuously on?

I work with accelerometer chips, a lot of them have features specifically for pedometers. Keeping the accelerometer on will draw a few uA, then you can have the accelerometer keep track of the step count internally and have the main processor query it as necessary to update the step count display. When there's no motion for a while, you can also put it into a lower power sleep mode that doesn't track steps, then when it detects motion it'll wake up the main processor which will then put the accelerometer back into pedometer mode. I think 2 years on a CR2016 (90 mAh) is reasonable if Casio knows what they're doing.

If it's like the G-Shock, it's not a real step counter, it's a small accelerometer. It will trigger on every single wave when you're planing if you're windsurfing, which makes it quite useless.

Looking up some generic step counters with LCD displays, they seem to last around 6-10 months on a CR2032.

Problem would be replacing it properly while maintaining it being waterproof.

With silicone gaskets this is not an issue.

It's not waterproof, merely resistant.