<p>Try preparing a little for the PSAT and take the PSAT your sophomore year. That should give you a benchmark of how much prepping you really need to do for the SAT.</p>
<p>I think you should start prepping for the SAT during the summer after your sophomore year because junior year is typically your hardest/busiest, so you won't have as much time to study. Plus, getting all your testing done before senior year would be a lot less stressful for you since you have to worry about college apps anyway.</p>