With Garmin watches, the GPS tracking is enabled when you start an activity. So you're not using it all day, it's for the hour or two that you're out doing some

With Garmin watches, the GPS tracking is enabled when you start an activity. So you're not using it all day, it's for the hour or two that you're out doing something. My old Fenix 3HR is good for close to a week with a daily walk tracked. My Descent G1 Solar (based on the [edit] Instinct 2 I think) is more like a couple of weeks with activities tracked. There are quite a few settings that you can tweak as well, depending on the model of watch. My Descent has most things turned on during the day, but switches most off automatically using a power-save mode configured to match the "sleep" time on my phone. I think if it's set to minimum power usage, it's closer to a couple months. (Estimated battery time is typically shown in the watch face.)