Here are a couple of free add-ons, well, tools, that can help your productivity.
When white is set to overprint in Illustrator files, such as white type or fills and strokes, it will disappear, since when white overprints black, the black will show through. This little plug-in will help you detect if you have white set to overprint.
For those that use MS Office programs, such as Publisher and Word, an easy way to create PDF's from Office programs is to install this handy print-to-PDF tool. Once installed, select PrimoPDF as your printer device, and you will get a PDF of your document. Make sure to select the Prepress setting for your PDF output.
To download the White Overprint Detector for Adobe Illustrator CS3 and CS4
To download the PrimoPDF plug-in for MS Office programs