If the concepts are understood quickly, shorter work sets to minimize repetition might help. IMO, if the substantive content is understood, it’s far easier to inculcate conscientiousness if the volume of work isn’t mind numbing. I also provide time-based rewards after work periods, so accuracy and speed net a larger reward. (Measure twice, cut once.)
One interesting discovery I’ve had recently with my DS is that he makes fewer sloppy errors on more advanced work. I try to ensure his persistence on a handful of basic questions is rewarded with a few truly hard problems that require writing out steps sequentially. He seems to love proofs and open ended problems.
