NY, you have to be an idiot to not know that your Di2 needs to be recharged. I know there were issues with some of the first models, but my DH has had his for 3 years. He rides 2-3K a year and really only has to charge it once, although he does do it twice. First a yellow light comes on, then a flashing red light, then a red light. Of course, you have to look at it, to check! I would not have gotten it, if there were issues and mine is a better model than my DH's, since they have made improvements. So, I would say, user error.
My Garmin stays plugged in all of the time, except when I am using it on the bike. I have 2 rear lights (the same model), that I interchange and charge after a week or so. That way, I always have one fully charged and ready to go. I have 2 different kinds of front lights. One is very heavy duty and if I use it in true darkness, like my 5 AM rides, on high, it has about 2 hours of use. However, I am rarely out for more than an hour in true darkness, and if I switch it to the lower setting, it more than doubles the time. I use it on flash mode, for late fall and winter daytime riding. My other light, which I use for daytime rides in the spring, summer, and early fall, is always on flash, so it lasts about 5 rides or more, depending on the length.
It poured today. My group ride was cancelled yesterday evening, due to the forecast. I did go to the new/old gym, signed up, and stayed for a step class, with some intervals with weights. I sweated like crazy. Friday I will go to an early morning boot camp, then co-lead the Friday morning ride. It's scheduled through September, but I can only do 2 more of them, after tomorrow. My women's group is starting back up on the 29th. It's only an hour and 45 minutes, so as it gets colder, I can ride after lunch, when I get home from work.