A Tip for Duplicating Pages
Direct from the obscure-but-useful-tips department: A really easy, quick way to duplicate a page is to hold down the option key (Mac) or alt key (Windows) while dragging the page icon in the Pages panel. However, there is a bit of subtlety to this that you should be aware of. If you option/alt-drag a page to the right of another page icon, you'll see a vertical bar indicating that the duplicate will be inserted at that position. Note that the hand icon doesn't feature a "plus" sign in this case to indicate the page is being duplicated, so it looks like the page is being moved. But as long as you hold down the option/alt key, the page will indeed be duplicated.
If you option/alt-drag a page after the last page of the document, you will see a hand cursor with a plus, and no vertical bar, indicating that the page will be inserted at the end of the document.
Here is where you need to be careful. If you option/alt-drag a page in the vertical zone between two rows of pages, or too far to the right of a row of page icons, the page will be duplicated at the end of the document.
So if you want to duplicate a page at a specific location in your document, be sure to option/alt-drag the page and move the mouse around until the vertical bar is displayed in the location where you want the new page to be.