according to:
https://forums.garmin.com/developer/connect-iq/f/discussion/255692/wf-limitation-app-battery-consuming
when simple app is running it consumes 5 times more energy than complicated watch face
everything with source code is in https://forums.garmin.com/developer/connect-iq/f/discussion/255692/wf-limitation-app-battery-consuming
but yes, one timer start by pressing button invokes every minutes function that
- inc values
- call requestUpdate
onUpdate() draw few texts