I love the fact that most productivity tips are focused on giving tips to people who have open schedules.
The #1 tip is normally schedule email time like that is something that people with a jobby job can do.
"No, boss I didn't see that client proposal or important work email that you're asking me about because I only check my email from 2-3pm because a "productivity expert" on YouTube told me to schedule email time."
I can see how awkward that response would be for a person to give.
However, I do like the do your most important task first advice. I try to incorporate that in my daily routines; especially at work.