shud i take more than once?

<p>I'm planning to take the sat subject tests for math level 2, physics, and chemistry, after i finish pre-calc, physics, and chemistry(all are at the highest level of difficulty before AP) in sophomore year(next year). Should I take them or wait till junior year when I'm in their AP level classes(calc ab, physics ap, chemistry ap)? Or, what i was thinking was taking them sophomore year and if i don't get the best score i can, i'll take them again junior year. What do you guys think?</p>