Years ago, my dad's hospital had a rule that the head of the department had to review all slides before you gave a presentation at a conference. The department heads had one consistent rule: they had to be able to view your slide without putting it in the projector and tell what it said. Worked pretty well: you can imagine how big and limited the content would have to be to be able to view it on a slide with the naked eye, and it kept people from filling slides with bullet points.