I try and skip them even though they can be some of the easiest questions because they're so formulaic and take so much time to solve. Sometimes I can spot the correct answer and rule out four wrong choices in 15 seconds, and sometimes it takes a small diagram and sometimes I can only narrow it down to two choices and have to re-read the stimulus a couple times to distinguish what makes one of them right and the other wrong. I make one exception, which is that I don't skip them when they're among the first 10 questions because those are usually easier than the parallel questions situated later in the test.