My son took Bio subject test after 9th grade honors Bio and scored a 790. He completed the practice test in the CB book, figured out which content areas he had not learned in class, then studied up on them a bit the two weekends before the test. However, he did not consider taking the Chem subject test after completing Honors Chem in 10th grade as the curriculum did not match up well with the Subject Test. I don’t know if this is just the case in our HS or in many schools, but we have very few students sitting for Chem subject test until after completion of AP Chem, whereas a fair number sit for Bio subject test after only completing Honors Bio.