Projects such as photo books, collages, calendars and cards are not deleted so long as your AdoramaPix account remains in good standing. It doesn't matter if the project is finished or not.
Photos that have been added to a project will remain within that project even if the gallery that originally contained them is gone. i.e. if you have a photo book that that contains images from a gallery that has expired and been removed, the images will still exist within that book. However, if you remove those images from the book, you will not be able to re-add them without uploading the image again.