I pretty consistently publish stuff that is ~180 dpi because that is what advertisers send. My preflight warns me, but no one has complained about the printed version so far…

Also I recently printed a section that had a few JPGs in it. I was hesitant to do it because of the aforementioned myth, but the PDF passed the preflight and the file did not cause a problem with the RIP, and the result was fine. Smaller file size too!

One myth that I was told over and over again was that PDFs have to be saved as .EPS files before they can be placed into a layout. As it turned out, this based on the fact that printing the layout made the .EPS files look crappy because they were a low-res preview version. Unfortunately a lot of the people I work with believe that a printout is always the ultimate version of anything.