It is advised to brush your teeth at least twice a day, but when? Just before bed is a gimme because you’re about to lie mostly still for 6+ hours. Best to not leave food particles to fester.
What’s the best time for an earlier brushing? After breakfast? After lunch? After work/school?
Plus, what’s up with TV and movies having breakfast scenes where they get up and head right out the door? Did they already brush and now they’re going to leave food to fester all day? Eww.
I remember reading that only once a day is necessary if you brush properly, but most people don’t brush properly, so the recommendation is twice a day to make up for that.