The battery in the chest strap for my Forerunner died recently but fortunately, unlike my old Polar, you can change it yourself rather than having to send it back to the manufacturer. I can’t help wondering whether it’s death may have coincided with the track I downloaded showing a route from the terminal building at McCarran International Airport to the end of the runway! I don’t usually pack the watch itself in my hold luggage and I don’t think I will be again.