In most cases, PDF files contain a large amount of redundant pages, pages which are useless and only add to the PDF bloat. You can have 400 pages in your PDF, yet need to work with only 30 of them. For the general user, this bloat and extra pages are a nuisance.
However, PDF tools are becoming more versatile and offering up more features that will let you work with your PDF. In fact, there are options you can try to make big changes to your PDF file size and content. You can, for instance, delete a page or a group of pages from a PDF file with PDF Converter Elite or Adobe Acrobat 11 Pro.