Getting Additional Guides

When you choose View, Guides, you see two guide lines that you can snap objects to for more accurate placement. You can drag the guides wherever you like them, but you're limited to just the two guides--one horizontal, one vertical. Wouldn't it be useful sometimes to have more guides?
Evidently Microsoft thought so too, because you can have more than one guide. In fact, you can have up to eight horizontal and eight vertical guides to place wherever you like, and it couldn't be simpler to do: Just hold down the Ctrl key while you drag an existing guide to a new position. The original guide stays where it was, and you get a new guide at the new position.