Good grief I grew up having to brush my teeth after every meal, when I got up out of bed and before I went to bed! So that was what? 5 times a day!
I started brushing ONCE A DAY at bed time fifty years ago. I use straight baking soda, no tooth paste as I can’t stand the smell or taste. I am 71, still have all my teeth. A few cavities before I started brushing once daily. Mom loved sweet cakes.