Re: battery life .... I did some work as a photographer and such. Batteries were everywhere ... in my laptop, in my cameras, in my speedlight, in my light pack, in my voice reorders.

Somehow I managed. No, no, don't worship me ... I am not a battery-management deity, I am merely a person who can think a tiny amount .... because that is all it takes.

There may be a lot of reasons for using or not using DI2 .... user error is not one of them.