Subheadings help while they organize genuinely distinct ideas and make a page scannable, and they dilute it once they start chopping a single idea into stubs or manufacturing structure over thin content. The line runs through whether each new subhead marks a real shift in idea. If it does, it earns its place by guiding the reader and breaking the page into navigable parts. If it does not, it fragments one thought into pieces that read worse than the unbroken version would have. More structure is not automatically better structure.
On the helpful side, a subheading does two jobs at once. It signals that a new idea is starting, which orients a reader moving through the page, and it gives someone scanning a way to jump to the part they want. When a page covers several distinct points, subheadings turn a wall of text into something a reader can navigate at a glance. That is real value, and it is why well-organized long pages feel easier to read than their length suggests.
On the diluting side, the same tool turns against you when there is no real shift to mark. Splitting one continuous idea across three subheadings forces the reader to cross artificial boundaries inside a single thought, which breaks the flow rather than aiding it. Worse is adding subheadings to make a thin page look substantial, where the structure is hiding the fact that there is not much underneath. Headings cannot manufacture depth; they only expose it or fragment it.
The assumption to drop is that more subheadings improve a page by default. They improve it only when the content genuinely divides into separate ideas. The pivot is always the same question: does this subhead introduce something meaningfully different from what came before, or is it slicing one idea for the appearance of structure?
When you edit, walk through the page and keep a subheading only where the idea genuinely changes. Where a heading sits over a continuation of the previous point, remove it and let the idea run, and where content under a heading is too thin to stand, develop it or fold it into a neighboring section.