Well Meaning, but inadequate.
I don’t like to give low scores to free apps: you get what you pay for. This one, that I used once only, has major flaws. It claims to "hear" your use of an electric toothbrush, whilst brushing most things it can, but tongue brushing does not register (at least with my tongue and toothbrush). Further, it requires you to have your phone close enough to "hear" your brushing actions. This (again, in my case) resulted in splashing of my iPhone. I’m happy to take my Apple Watch into the bathroom but more reluctant for my iPhone to visit. This needs a watch app. I won’t be using it again, but it does suggest a good brushing strategy.