A keyword variant deserves its own page when its intent or its search results genuinely differ from the head term, different results ranking, a different searcher need, and it does not when the results page is essentially the same as the head term’s. The pivot is different-intent-or-results. When the variant truly diverges, build the page. When it does not, it belongs as a section on the existing page or stays folded into the head term, not spun out as a separate URL.
The instinct to make a page for every variant in the name of coverage backfires, because most variants are not separate needs. “Affordable standing desk” and “cheap standing desk” are different words for one intent, and the results pages for them look the same, so two pages would just compete with each other for a single audience. Coverage that splits one intent across two pages is not more reach, it is self-cannibalization, and it weakens both pages relative to a single page that owns the intent cleanly.
The variant earns a page when the searcher behind it wants something genuinely different. “Standing desk” and “standing desk for tall people” can diverge: the second has a distinct need, likely surfaces different results, and supports content the general page would not naturally carry. That is a real intent with its own results page, so a dedicated page serves it better than a buried section. The deciding evidence is not how different the phrases read but whether the results pages and the underlying need actually part ways.
So before splitting a variant off, compare its search results to the head term’s. If they return the same kind of pages for the same kind of searcher, keep the variant on the existing page or as a section within it. If the results page and the intent clearly differ, give the variant its own page, because then it is a distinct need rather than a synonym. Check the results first, split second.