Similar-language regions should get separate pages only when there is genuine regional difference worth distinct content, and a single page otherwise. The pivot is meaningful-regional-difference. Two regions sharing a language, such as the US and UK, or Spain and Mexico, do not automatically justify two pages; what justifies them is whether the content actually needs to change for each audience. When it does, separate pages plus hreflang serve readers better, and when it does not, one page serves everyone without the overhead.
Separate pages make sense when the regional differences are substantive enough to change the page’s value to each audience. Different currencies, region-specific examples, local spelling conventions, distinct offers or availability, region-specific regulations, or different shipping and pricing all give each version something genuinely its own to say. In those cases a single page would either show wrong information to one audience or read as a compromise that fits neither, and separate, hreflang-linked pages let each region get content tailored to it.
One page is the better answer when the only differences are trivial. If two regions would see essentially the same content with no meaningful divergence in currency, examples, spelling, or offers, splitting them produces two near-identical pages that risk competing with each other and add maintenance for no reader benefit. The default reflex to “make a page per country” tends to manufacture thin duplicates rather than serve anyone, because without real per-region content there is nothing for the second page to do. A single well-written version that works for all the regions is simpler and avoids self-competition.
Split only where the regional content genuinely differs. Audit what would actually change between regions, currency, examples, spelling, offers, availability, and if those differences are real and useful, build separate pages connected with hreflang; if the content would be essentially the same, keep one page. Let the presence of meaningful regional difference, not a country-by-country instinct, decide.