That’s gonna be different for everyone. I do studio work with products, and 9 times out of 10 we have concept illustrations we’re working off of so the client can approve before we even touch the camera. Because of that, I don’t really fire off shots that I’m not using.
Ask me to shoot a football game though and I’ll probably hit 1 out of 1000 shots lol
I interned at a large studio that did catalogs for brands like Walmart and bed bath & beyond while I was in college, and most of my schooling was focused on products and studio photography. I built up a portfolio on my own, and around 2015 I started posting my work on IG and tagging the brands who’s products I used in photos. Some brands noticed and started hiring me for campaigns and it snowballed from there. My business has evolved a bit over the years to follow the money, but that’s how it started.