Just do a google search for the title of this post.
This is practically the most favorite thing for would-be photographers to talk about on the internet. They seem to like to rush down the rabbit hole and misunderstand one another, and say stuff that is perfectly correct if you happen to understand there are seven separate things left unsaid which have to absolutely be a particular way.
Why? Who the fuck cares? These just no goddamned point to this shit. If you have a specific application where you need to have a specific depth-of-field, hie thee to a calculator and get your answer.
If you do not have a specific application, then surely your sensor size and focal length and where to stand are pretty much a given, driven by a thousand other factors. Then adjust the aperture to produce the desired depth of field.
And none of it has any point at all unless you happen to know how you're going crop the frame, what size the final print it, and what the typical viewing distance is.
If you don't know those things, at least roughly, then the entire discussion is pure masturbation.
So why to people waste so much time on this crap?
My theory is that it hits some sweet spot for the gearhead nerd. It's complicated enough that nobody can actually explain it perfectly - some tiny detail, or some not so tiny details, always get left out, opening the door to arguments. And who doesn't like fighting about bullshit on the internet?
It's simple enough that one can (mostly) understand it in full, if you struggle a bit. So now you have something to lord over the slightly more new, something you can use to pretend you know more about photography.
DoF "discussions", just say no.