Hello, there. I believe meaningful experiences will hardly be forgotten. For instance, when someone starts growing into an independent (young) adult, even in the face of adversity, it's difficult to not store this experience as an enduring memory, especially if it's something that contributes to your growth as a human being, and to the reaching of your goals. I guess it depends on the person, but I've met people with the sharpest of memories, and the experiences seemed to be meaningful.
Regards.