One consideration is that, in darktable at least, each image operation has a fixed place in the processing pipeline, so that two seemingly similar modules may play slightly different roles.

A good example is "base curve" vs. "tone curve"; the former functions very early in the pipeline, meaning its output will affect what's seen by the color matrix (affecting saturation, etc) as well as most other modules that vary their behavior depending on the tonal range they're looking at (shadows and highlights, for instance). On the other hand, "tone curve" functions near the end of the processing flow, operating on the output of all the other processing up to that point, so it might make sense to use this nearer the end of your workflow for fine-tuning of black/white points and overall tone curve.

You can observe the processing order of the modules in the right pane, the flow being from bottom to top. To see the relative order of modules from different groups, enable them and select the "active" (left-most) tab at the top of the right pane.

Of course, this only addresses one aspect of your question; What order you should make your adjustments in is a more complex, subjective topic, but understanding what's going on "under the hood" is a good basis for developing your personal workflow.