The schematic shows an RTC in there, does it really need to have its timekeeping syncronized every day next to startup?! Or it's just something you do to cover for eventualities?
Maybe I'm doing something wrong but the RTC lags about a minute every three days. At least for my device a regular ntp sync is therefore absolutely required.
Some v1 units got defective RTCs so one would have to frequently sync time. My version had around 2 weeks of battery life (no ntp/etc). I can see getting way beyond that with accel and on-demand refresh instead of 1min intervals.