*Author’s Note: While this article refers directly to the SAT, all of this advice is jointly applicable to the ACT. It merely says SAT for purposes of brevity and simplicity for readers!
There is no perfect formula for acing the SAT. Each person approaches the test differently and will have different results upon taking the test more than once. I have some friends who took the test 8 times, improving with each and other people who took the test 5 times and scored within the same 40 points each time. There are vital considerations you should think of when taking the SAT. Once acknowledging these, you must balance the pros and cons of each. If your dream school requires you to send your entire testing history (like Georgetown), you should probably avoid sending many tests.
There are different circumstances with practice exams and the real deal. However, you need to make the most of your practice exams by going into each extremely well-equipped. Before taking (or rather, signing up for) your next SAT, make sure to have taken a timed, complete test as close to testing conditions as possible and adequately grading it. With this information, you will have a better sense of how you'll do on the actual exam. It is my advice that you should never go into a test without an idea of how you will do. Not only are you spending money, valuable time, and brainpower to take the exam, but you are risking adding unnecessary (and potentially poorly scored) exams to your testing history. Perhaps this school will require your full testing history. For this reason, it's always better safe than sorry, and you should be thoughtful in the number of times you take the official exam.
I have spoken to tutors who believe that three is the maximum number of times you should take the exam. They believe that beyond three exams, there is little chance in raising your scores. This may be a good rule of thumb, but keep in mind that your circumstances play a huge role in how you do on the test. If you are taking exams during the school year on top of a demanding course load, then it's not a bad idea to take a fourth exam over the summer when you have more time.
You do not have to retake the exam if you are happy with your first score. I took the exam once and found this to be a significant reduction to my stress junior and senior year. Getting it out of the way allowed me to focus more on my extracurricular activities, AP courses, and other aspects of the college process.
It also depends on who you are as a student. If you are not willing to put in additional time to study and re-prepare yourself for the SAT, it is probably best to devote your attention elsewhere. While these exams are a part of your application, not everyone is a stellar test-takers. College admissions counselors know this; you know this. You know what the best and most efficient use of your time is and it may not be studying to take the SAT an additional time. Take this knowledge and use it to motivate yourself to do something else productive; to show admissions counselors your passion for another activity or to raise your GPA!