When I write psychological evaluation reports, I start with a template that has headings for the various sections. Until now, I always had to check the document before printing to make sure that no headings were alone on the last line of the page, with its accompanying paragraph on the next page. It did not take much time to fix the problems, but it was a pain to re-paginate the report if I made future edits. Its main cost was a bit of worry each time I finished a report.
All these years it never occurred to me to ask whether Microsoft engineers had anticipated this problem!
In Microsoft Word, there is an option to keep a paragraph on the same page as the next paragraph. I use Word 2010 for Windows so your experience might be slightly different. I select the heading, and click the format button in the Paragraph section.
Then click the Line and Page Breaks tab.
Then check the Keep with next box.
Now right-click Heading 1 on the Styles portion of the Home tab on the ribbon. Select Update Heading 1 to Match Selection.
Now everything you have marked as a Level 1 heading will stay with its accompanying paragraph. You can repeat the process for Level 2 and Level 3 headings, if needed.
I have now updated my template so that the headings behave properly.
A more thorough treatment of page breaks and other pagination tricks can be found here.