I'm taking the ACT for the 3rd time soon. If I don't reach my goal on this next test, would it be a bad idea to take it a 4th time?
While can you can take the ACT up to 12 times, that doesn't necessarily mean that you should. When you're deciding whether or not to sign up for the ACT a fourth time, you should consider the following points:
What is your target ACT score? Your target score should be based around the colleges you're applying to, not some ideal number you picked out of thin air. For instance, if the colleges you're applying to have average student ACT scores of 26, there's no need to obsess over getting a 36. For more about finding your target ACT score (including a free, downloadable worksheet), read this article.
How likely are you to improve your score on the next test? If you just keep doing what you were doing before you took the test the first three times, chances are your score isn't going to improve. On the other hand, the less you prepared before taking previous tests, the more likely you are to do well on a retake that you've studied hard for. Learn more about the factors you should consider when deciding whether or not to retake the ACT or SAT here.
Unless you're applying to an Ivy League university or certain other top colleges (like Pomona), you won't have to send all of your ACT scores when you apply - you only have to send your highest scores. So if you believe that you can put in the time to study effectively and raise your score, go for it! Otherwise, call it a day after 3 tests.