During a long plane flight to San Francsico I could see a number of people editing their presentations while stuck in the air for more than 10 hours.

Many of them were editing the exact sequence of what they were going to say to the audience. Changing a sentence, switching the order of some bullet points: they were editing speaker notes, not editing slides.

This type of editing should be done in the notes field of the slide, not on the slide itself. It is a good check for yourself: if you find yourself editing speaker notes in the slide itself, you are probably doing something wrong.