I almost always read in the news/press that dentists recommend to brush teeth two times a day for 2-3 minutes.
This drives me crazy, because it does not make sense; The point for dental health is to systematical clean every surface of your teeth twice a day (and use inter-dental brushes/floss once a day). For me, brushing my teeth takes around 6 minutes, if I hurry up. For someone faster it might be possible in 1 minute.
So, why do dentists always give the 2-3 minutes recommendation?
In a sense, I guess op is right though — I recently read that ~70% of people in a study were brushing ineffectively, no matter how long they were told to brush. Their brushing only improved after being told to make sure to brush every every “sector” of their teeth.