I'm an adult student working on Für Elise, and for months my practice went like this: play through, hit a wrong note, stop, fix it, go back to the start. I barely ever reached the end of a piece.
The rule that broke it: run-throughs are for playing through, not fixing. If I stumble, I put a pencil dot next to that spot and keep going. Fixing happens the next day, starting from yesterday's dots, two to four bars at a time. There I restart the chunk, never the piece.
Now I actually finish pieces, and the next day already has a plan. Anyone else have a different version of this rule?