If the goal of reading is personal enjoyment, then rereading is simply a personal choice.
If the goal of reading is to be more productive, then what matters is your ability to remember the text. In this case, active recall and spaced repetition are far more efficient than rereading.
If the goal of reading is to be more productive, then what matters is your ability to remember the text. In this case, active recall and spaced repetition are far more efficient than rereading.