No, no, I'm not done talking. I'm never going to be done blathering on and on about things. Don't worry!
Ambrotypes, tinytypes, Daguerreotypes, all these processes share the same general shape: You make an exposure, you follow a series of well-defined steps, possibly with some variation along the way for artistic effect, or not, and then you are done. The result is a unique object, which exists, sui generis, and is essentially immutable. You've made the picture, it is what it is, there is no more.
Glass negatives, film, and wet darkroom work began to change this. Now you could, and still can, revisit an exposure. You can break out the negative, load it into the enlarger, pour out some chemistry, and start burning money on paper. So there's some dis-incentive, at least, to endlessly revisit a picture. You need to have a bit of motivation to go pull some new print from and old negative. There is real effort, time, and money involved. So, even though it is not impossible to tinker forever, you are generally motivated to declare a picture done at some reasonable point.
I find myself, mostly, to be done with a negative after I have pulled satisfactory prints from it. When I am motivated enough to get my hands wet and ruin paper, there is always a new negative I could work on.
Digital has altered this, fundamentally. There is now almost no barrier to going and reworking an old picture. People can and frequently do revisit an old picture merely because they are bored. In the modern "correct" conception of digital, you're shooting RAW (because you have to! everyone serious shoots RAW!) you can back quite far toward the beginning of the process, and re-imagine much of the exposure. With enormous pixel counts, you can re-frame the shot with a crop. You can damn near go back in time and re-shoot this thing.
The online environment in which we now share and critique one another's pictures assumes this malleability. Critique from "serious" photographers almost always boils down to unwinding and re-working. There is no recognition of the idea that a photograph might be done and that perhaps we could talk about it as it exists.
There is almost no pressure on you to declare a specific picture done, the door can always be left open to go back. If you share your pictures online, you may find yourself urged to back through the door, again and again. The default critique, online, includes "go back and tinker with the picture". Rather than influences urging you to declare the picture done, there are instead influences urging you to never so declare it. Somewhere between 35mm film and the DSLR, the pressure changed subtly, just enough to reverse the direction.
Anyone who has written software professionally knows that a lack of a firm endpoint is not freedom, it is not luxury. It is to be strapped eternally, screaming, to a great burning wheel. It is a terrible fate, although it often feels like luxury and freedom. You will endlessly chase perfection, you will endlessly tinker, and after a while you will imperceptibly begin to make things worse rather than better. Eventually your software has 1000s of features that don't quite work, and your photograph looks like a ghastly plastic object with no concept, no idea, and no reference to the original scene.
A project I am currently working on involves some rules I have made up for myself. Among them are that I shoot the picture with my phone, that I edit on the phone, and then I am done. The picture either is, or is not, good enough. My phone has a very decent camera, the editor isn't photoshop but is surprisingly capable for a phone app, and the ultimate portfolio is aimed to be 6 very small pictures, more or less. So, I have more wiggle room than you might think.
The salient point here, though, is that the rules include: And then I am done.