pianoloverus In terms of classical music once one reaches a certain level, maybe somewhere around ABRSM 7 ....
I addressed aspects of this in a recent post. We have here a picture of someone being taught in a sequential manner, I think I wrote "prerequisite built upon prerequisite", and this, done under the guidance of a good competent teacher. In that case, when you reach "grade 7" you have a known set of skills and required knowledge. This will tell you which pieces you "can handle".
If you did go through a system like ABRSM, but with poor or shallow teaching, you might not actually have gotten those skills. You may even have been mistaught some things which will be obstacles. These systems like ABRSM, RCM, AMEB etc. are merely frameworks.
Many of us didn't even get that. Our abilities are "all over the place". The path is less straightforward, and abilities and lacks are also less predictable. That said, I opted for myself to go to the beginning, and always to look toward fundamentals as the key to unlock doors.
What I tried to address in this topic was the idea that HOW we work on a thing may also have a major impact on what we're able to reach, including what we're not able to reach. This question has many sides.