<p>Jan of Jr year is the best time to first take the SAT for a number of reasons:
1]
You will already have 1/2 year of tough courses under your belt [ including AP classes for many students] and you also have time during the Xmas break to do some practice SAT exams, without the distraction of homework as well.
2]
IF you want to repeat your SAT test, you have 2 more times - March and Oct. to do so that would not conflict with subject test dates. Subject tests SHOULD be taken in May or June of the year you took the class , when the material is still fresh in your head- not in Oct- AND you can NOT take SAT AND Subject tests on the same dates. So, for instance, if a student taking APUSH, an AP Science class and an AP Foreign Language or AP English language class wanted to take the corresponding subject tests [ which is recommended because its like killing 2 birds with one stone] - that student is likely to want to spread the subject tests out between the May and June test dates- there by eliminating those dates for retaking the SAT. </p>
<p>If you need to retake the SAT, Oct of your SR year is the best time, because you will have even more learning under your belt than in JAN, and are likely to do better than you did 9 months earlier.</p>