Ready for a crazy statement?
The purpose of quality study-practice is NOT to make sure you never make a mistake. The purpose of quality study-practice is to make sure you know the music so well that you can keep on playing like it’s no big deal when you do make a mistake!
No one is suggesting that you walk into a performance unprepared. Quite the contrary. Do your best to prepare, but accept that honest mistakes are part of being human and study-practice accordingly. This is a vast subject on its own, already presented in the series: How to Study-Practice.
Anyway, back to our topic…
Your capacity to handle the inevitable mistake is like having a spare tire. Hoping you will never get a flat tire is not a good plan, but having a spare tire just in case reduces your anxiety immensely and gives you a whole new level of confidence that you can get no other way.