Rather than speed-watching, Dr Horvath suggests: “If you watch a show … don’t binge it, spend a day not watching the show, thinking about the episode you just watched, predicting what’s going to come next.”
Personally, I listen to podcasts at 1.5 – 1.7x the speed, unless they involve music. Then it is 1.0x. I feel the issue is not the speed, but whether I am concentrating when listening. However, I was also left challenged recently by whether it was really humane to listen at speed. I cannot imagine watching a film or a series at speed though.