pianoloverus And also depends on how secure you want the memorization to be. It's one thing to memorize a piece that you play just for yourself or for your teacher where a memory slip is not going to be so important versus memorizing a piece that you will perform in front of a lot of people In a recital or competition.
This is also a really good point! I have never played in a competition, and the only pieces I memorized for recitals were a long time ago when I was playing beginner level music.... I think I mentioned above that the last time I had a few memorized pieces was when I was piano shopping, and I did that so I could audition pianos with the memorized pieces. Well, to me, playing in a piano shop is at the level of playing for a teacher, or maybe even less. Actually I was surprised to realize that I was not nervous at all when I was playing while piano shopping. I guess I knew that I was the customer, and I had money to spend. So it was a very different dynamic.
All that to say that I personally have never experienced playing an intermediate or above piece from memory in a high-pressure situation.
And I probably never will! I certainly will be playing from the score when I play my two pieces at the recital next month!