Very easy to schedule an appointment. I did extra strength for 50 minutes and did not see a noticeable difference in my teeth, took pictures in different lighting to make the effect of it. (I don't smoke or drink coffee or red wine so my teeth aren't very yellow, but also heard an older women complaining that her teeth didn't noticeably change either) I also got strep throat right after, it may be a coincidence but wanted to post Incase anyone else was getting sick too.