I don't carry anything on me I don't feel I will need. This includes removing tools from my tool belt that I don't intend to use. I have done this work for enough years to realize that carrying extra weight wears you out over time.
This does not mean I won't bring things from truck inside to work area so they will be handy when or if needed, just if it will require little or no use why carry it around all the time?
I should add the apprentice I have working for me has a tool belt that at times probably weighs 25% of what he weighs. I am a lot heavier than him but that is too much to carry around all day.
I'm always amazed when I see guys roping a house, and they have a laser level, three concrete chisels, tinsnips, a pipe cutter, a pair of 460s, three files, two crescent wrenches, and a tone set in their pouch.