Sometimes when I have only a few minutes I might scan a few quizzes to see if there are any that can be easily dealt with, without taking a lot of time. If a quiz is going to take more time than I have at that moment then I will back out.
Now this doesn't necessarily mean that the quiz requiring more time is in worse shape than the one requiring little time, the reverse could actually be true as well!
"To insult someone we call him 'bestial'. For deliberate cruelty and nature, 'human' might be the greater insult." - Isaac Asimov