Even for short documents, it's worthwhile to create master pages and styles if you have to create new versions with different copy frequently. Each of the three programs handles master pages somewhat differently. All three programs let you duplicate existing master pages to create new ones, but only FrameMaker can duplicate a document page as a master page. And all three programs let you place an automatic page number character on a master page that inserts the real page number on each document page. The thing to remember is that if you find yourself adding a specific element or creating a text box of a certain size on more than one or two pages, making a master page will save you time in the long run.
Style sheets are a more complex matter.
Paragraph styles include several sets of attributes and let you format each paragraph with one click or, in the case of QuarkXPress, one keystroke. The fastest way to create a style is to format a paragraph the way you want it, then create a new style while that text is selected. You can also take advantage of the ability to base style sheets on other styles, but think carefully before you do so in QuarkXPress or PageMaker, which maintain a dynamic parent-child relationship. It may make sense to base numbered and bulleted list styles on the basal paragraph style, but basing heading styles on the paragraph style will be a nightmare if the typeface for the paragraph style changes but not the typeface for the headings. FrameMaker is a different story, because it doesn't maintain that relationship.