As I’ve mentioned, I’m an SAT/ACT tutor. I’ve been doing this for over 10 years. Plus, 4 of my own kids have gone through this. I say this because I do feel I speak from experience and proven results. People should feel free to disagree with me of course.
I do not feel you should take both ACT and SAT unless there is a compelling reason to do so. If you want to find out if you do better in one or the other, just take full practice tests in each. It will be obvious. (If it’s not, choose one you like better.) Then throw all your efforts into one. You only have limited time. If you use that time to prepare for both tests, you have less time for each. They are quite different. Yes, student x or y could have taken both tests and done well (for whatever reason), but this is not advice I would give generically to all students.
I’m not sure people appreciate the amount of study and prep some students put into these tests. IF you go in cold, you are competing with someone equally bright who has studied for 6 months. If you audition without practicing, no matter how talented you are, you are putting yourself at a disadvantage, sometimes a major disadvantage. Same for SAT/ACT. Yes, sometimes you get kids who don’t study at all and get near-perfect scores, or study very little. But that is rare. It stands to reason that most students will do better with preparation and practice. Some students, particularly those who are rusty in some content and/or are not natural test takers, will do far better with practice.
I intensively teach both content and strategy. You can learn this yourself if you’re motivated & a strong self-learner (there is tons of info online). Or you can take classes. But you need to aggressively practice. You first diagnose the problem(s) and see if there is a pattern to your wrong answers. If you’re weak in content (you’ve forgotten basic algebra or you don’t know grammatical rules), study content first. The prep booklets by any number of companies have a lot of info. There is also tons online. Once you are strong in content, or concurrently, study strategy Again. the test prep books (like College Board’s, or Princeton Review or Kaplan or whatever), have many strategy tips. Diagnose your patterns. If you find you are getting questions wrong because you’re not reading the question carefully, be sure to do that next time. Or you might not be reading all the answers. Do that next time. etc.
If you don’t want to do that it is totally fine. And I certainly don’t think these tests necessarily indicate anything about your intelligence, drive, creativity, etc. But boy is there a lot of money in these tests. My own kids would never have gotten into the colleges they did, with the large grants they were awarded, without their high scores.
If your kid is not a high scorer and never can be, fine. I’m only saying that it is a good investment of time to study. Wherever you are, you can improve. I recently tutored a kid with disabilities, whose score was below 1000 for all 3 tests. After tutoring, he went up to 1350 for all 3, including a 490 in reading (this from a 340). This is a huge increase for him.
Whatever you decide, best of luck! There are so many pieces to this process.