I agree that changing the appearance in some way is a useful technique. I picked up errors and issues with the flow of words and thoughts when I read my manuscript draft on my iPad instead of the laptop screen. It was helpful as a paper saving option before I printed it out for another round of proof-reading. My only complaint was that, on occasion, my iPad would split a hyphenated word or a word with an apostrophe into two at the end of a line. That was interesting. The text-reading option is great for highlighting homonyms/phones/graphs etc and those pesky miss ended. On a side track, my mother always struggled with punctuation, yet she was a faithful letter writer. She tells the story of writing a letter to her intended when they were courting. At the end, she filled a line with punctuation marks, suggesting he use them where needed to compensate for any she had missed or misused. Clearly her sense of mischief and humour worked, because she got her man.
LOL - Love your mother's story. I remember you saying that you used some software that read your novel to you and that you picked up things you wouldn't have otherwise. Was it Dragon? I'll have to try that when I finally finish my draft. That's a good idea too about reading your work on different devices. Anything to make us see (or hear) the manuscript differently is useful. Thanks for commenting :)