Sat words that come in your collegeboart SAT exams

Collegeboard is no idiot to repeat the same difficult words on SAT exams every time. The most difficult ones on one year say 2009 will not come in 2010. However there are common words that appear every once in a while in the real SAT. I do not understand why they are repeated? Might be that the test makers think they are no big deal or they just are so common to them that they do not even hesitate to remove them. What ever the reality might be, for an average guy those words might improve their score in critical reading by 50 or 60 may be.