Twice: after waking up,before bed. Floss, tongue cleaner , mouth wash is a part of the ritual. On a related note : can recommend electronic tooth brush.
The amount of individuals here who brush post breakfast or not at all in the morning is alarming ! Of course, mental health can affect the schedule but that’s a different conversation and is understandable.
The rest, how is your dentist not harassing about your oral hygiene?