I have 30 odd lithium polymer cells with capacities ranging from 70 to180 mAh similar to what is used in Bragi devices. These are used in micro airplanes and helicopters. I’ve never gotten over 2 years or about 300 charge cycles out of a cell. These cells are discharged at a higher rate in those applications. Their best longevity requires that they are never excessively charged or discharged and when stored, are done so discharged to about 60% of full charge.
I’m hoping that Bragi was really conservative in limiting maximum charge cut off voltage and allowing a relatively high shut off to ensure longevity. Ideally, storage mode in the charger will allow a less than full voltage to permit an optimum number of charge cycles. Leaving the Dash in the charger and topped off to 100% for extended durations is going to be detrimental to the service life of the cells. This is why I’m hoping that the full charge cutoff is limited well below the maximum. Most high end lithium cell hobby chargers have a storage mode which charges or discharges cells to an optimum voltage/capacity.
I wish that Bragi published suggestions as to when to use their storage mode and explained what it does. My DJI drone batteries automatically self discharge fully charged batteries to their storage voltage in 1 to 10 days based on a selection you make in the app. If you charge 3 batteries and you can only use one or two or even none before dark or inclement weather, they will safely and slowly self discharge to their best storage level after the number of days you have set.