Indexed pages are an asset when each one adds unique value and meets real demand, and they turn into a liability the moment they are thin, duplicate, or low-value, dragging on your quality signal and wasting crawl. The line is value per indexed page, not the count. More pages stop being more SEO the instant the marginal page adds nothing, because at that point you are not expanding your reach, you are diluting it.
The assumption worth dropping is that every indexed page is extra surface area working in your favor. A page only helps if it earns its place by answering a query the others do not, or serving demand the rest of the site misses. A page that duplicates another, restates a thin answer, or exists only because a template produced it does not add surface, it adds drag. It contributes to the search engine’s overall read of your site without contributing anything to the people searching, which is the worst trade in the index.
So the boundary sits at the marginal page. Ask what the next page brings that the existing ones do not. If it carries genuine unique value and there are people searching for what it answers, it is an asset and growth is real. If it overlaps an existing page, splits an intent that one page already owns, or fills space rather than need, it is a liability the moment it indexes, regardless of how it lifts your total page count. Ten pages that each own a distinct, demanded answer beat a hundred that blur into each other.
So judge your index by per-page value, not by how large it has grown. Before publishing or indexing the next page, confirm it adds something unique people actually search for, and hold pages that fail that test out of the index. Growth is only an asset while every page on the pile is still pulling its weight.