Carrying spare AXS batteries

[weaponsgrade]

I just stepped into the 21st century with AXS. Who here carries spare batteries? My Garmin head unit shows the charge levels of both the derailleur and shifter batteries so I don't really see the point. Have people found the indicated charge levels to not be accurate sometimes? I've only got a few hundred miles in and so far everything is showing fully charged. Part of me didn't want to like it even though I bought it, but so far things have been flawless. There's a little bit of noise in the lowest cog, but I think I just need to adjust the gap.