Not sure what you mean here. I shoot a ton of concerts in large venues for big acts and I don’t care how the sound man does his job. Sound is his job, images are mine. End of story.

I expect a second shooter to know their camera inside and out. Be able to shoot in constantly changing conditions with no hesitation. I expect them to understand composition, depth of field for storytelling, and etiquette as far as how to shoot without being in the way of anything. A second shooter should not be an amateur shooting in automatic mode trying to build a portfolio. A portfolio should already be built so I know who and what to expect when I am hiring.

There are hundreds of types of photography and some have potential to make more than others. What do you shoot? Kids? Families? Sunsets? Hard to offer advice with such a broad statement.