Unless you're changing the page setup via Section breaks, all pages in a Word document have the same height. And even if you're using Section breaks, each Section can be formatted so the pages have the same height.

So it's not apparent to me what you think you'll achieve via a macro that inserts page breaks other than complicating any future edits to the document. Indeed, what you risk is having page breaks splitting paragraphs and, when you switch to a different printer, having the page breaks being pushed to the tops of the next pages, resulting in empty pages in your document.

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Cheers,
Paul Edstein
[Fmr MS MVP - Word]