if you're using all valid characters (numbers, punctuation, upper and lowercase, etc) then every extra character grows the set of possible passwords exponentially, not linearly. 24 characters is a huge problem space, i don't know exactly how many possible characters there are but let's say it's 50, so that's 50^24 which is 41 digit number, a number so big I don't know what to call it and still in the realm of a password that would take so long to crack you would die before it was finished cracking.