There are so few teachers who are capable of inspiring children to learn things for themselves that it only takes a couple of weeks a year for them to learn such a basic concept that holds the reward of lifelong learning. Far too often teachers demand that students dowse their quench for knowledge by requiring them to hold to standards of education that are designed to meet the needs of the mediocre.
I wish I could convey to you how severe my frustration with an education system that rewards aceing tests with "C"'s because the required mundane homework assignments were not completed as assigned. The education system I experienced was designed to steer people towards meeting in the middle and did nothing to encourage students to succed on their own.
So how about this? Would you consider a few weeks long test out period for students who just don't want to listen to you rehashing concepts for months on end that they have already mastered in just a few days?