I wait until I have a couple hundred or so after sorting some lots. I'm not smart enough to do the math if it's 20 cards out of 598 and the number are spread throughout...lol. Plus loose sheets can damage cards.
I can tell you one thing...as you put cards in a binder make sure the last card on each page is divisible by 9...
don't want to go 100 cards deep and have to move everyone back one spot! Tip...all numbers that are divisible by 9 add up to 9. Important tip as you input cards. #369....3+6+9=18, 1+8=9. #432...4+3+2=9. #618....6+1+8=15, 1+5=6. UH-OH...you now know card #618 should not be in the last spot of a sheet...haha. Trust me...this math matters...