Sawzall and cordless impact drivers were game changers for me. When they first came out I was skeptical. even had my first impact driver a year before I used it. No way will I be without either now. In fact I take 2 impact drivers out to a project, just in case the first one breaks.
Yup I agree, battery operated tools on a jobsite are game changers. I had 18v Drill, Sawzall and circular saw, 28v metal circular saw and 12 v impact and ratchet out of my truck most of the week. Never charged one battery. The ratchet rules doing strut clips. Metal saw, 3/4 rigid conduit and strut, cuts it all day long. Probably should charge some batteries this weekend for next week but gone are the days of corded tools for me when on the job. In fact I rarely use corded tools in shop.