There needs to be an option to temporarily flatten an image for saving/printing only.

Once again, I've accidentally closed photoshop after flattening an image to print.

Most of my typical projects will be saved as either 11x17 or 24x36 pdf. I usually just flatten the image, print, then undo to retain all the layers and edits, since I know I'll be making minor adjustments here and there. 

I've read many posts about duplicating the original file first, then flattening the copy... and it just seems more tedious than "good practice." Why can't that there be an option for saving to pdf that allows the project to be temporarily flattened, then revert back to the original once the print is complete? Wouldn't that eliminate the need for duplicate files? I recognize when saving to jpeg it automatically flattens the image, but why not provide that option for pdf?