Garmin Vivofit 4

The most activity trackers keep you active - more in recharging than for doing sports.
The Garmin Vivofit 4 is an activity tracker that needs to be recharged only once in a year.
This seems to be a unique selling point. That is in fact a comfort for the user, but after a year you probably have forgot where you put the charging device. Or it is competition day and you didn't know that the device has been already one year without charging in operation.