From LivingPianos.

https://livingpianos.com/why-you-must-practice-perfectly-3-times-in-a-row/

Welcome to LivingPianos.com, I’m Robert Estrin. The subject today is about why you must practice perfectly three times in a row. This is really important for any of you who want to develop consistency in your piano playing. So often, when I’m working with students and they come to a passage they are having trouble with, they play it a few times with issues, then finally, they get it right, and then go on. If you played it and missed it about five or six times, and got it right only once, what are the odds you’re going to get it right again? Only one in six.