When you’re writing within a specific page count in InDesign, you probably want to know if you’ve run out of room at the end of the document. While InDesign provides an overset text indicator in a story’s last threaded text frame, you aren’t going to see that indicator as long as you’re writing on another page somewhere in the middle of the document.
The slow way to check that overset text indicator would be to go to the last page, look at the indicator, then choose Layout > Go Back to return to the page you were on. You may find it faster and easier to open a second document window displaying the last page of the document, and keep it around behind the window containing the page you’re actually editing. To set this up, choose Window > Arrange > New Window. Now you’re seeing the same document in two windows. In one of the windows, go to the last page in the document. You won’t be changing that window’s view.
Now switch to the first window; as you edit the text you can check on the last page at any time by switching to it and switching back. Of course, this is very fast if you use the Command+` (Mac) or Ctrl-` (Windows) keyboard shortcut to flip through the open windows in InDesign CS4, because InDesign won’t lose your text insertion point in either window. Just flip back to the original window to continue editing.
I use this so often that I used the Edit > Keyboard Shortcuts dialog box to create a keyboard shortcut for Window > Arrange > New Window. When I want to create a last page window, I just press the shortcut for New Window, press the End key to get to the last page, and press the window switch shortcut to get back to editing. Once it’s set up, whenever I want I can press the window switch shortcut a couple of times, once to check my story length and again to return to editing.
If you want to simultaneously view both the page you’re editing and the last page of the document, you can use the window management commands in InDesign. If you using floating (not tabbed) documents in InDesign CS4 you can choose Window > Arrange > Tile. If you’re using tabbed documents, you can click one of the n-up options in the application bar to instantly display both views tiled side-by-side. The only reason I first talked about flipping between two overlapping windows is because I usually prefer to use the entire monitor to see a double-page spread at once, but if you have own a very large monitor you might prefer to tile your documents so you can see them together.