Some discussion in this 2018 article, https://hackaday.com/2018/12/03/why-is-continuous-glucose-mo...
https://idoroseman.com/freestyle-libre-blood-glucose-monitor...
> The sensor life is limited by the amount of chemical coating on the probe and the amount of glucose in the interstitial fluid. It could last longer for a person with low and steady BG than for one with chronically high, so the sensor life is a conservative compromise between battery size, Bluetooth wake cycles, and probe life. If the probe had a larger supply of reactant or its dispersal rate could be slowed, the sensor life could be extended to the battery capacity or the max that the FDA would permit.