Again, this would be a subjective choice depending upon how arduous you are in communication and all its forms as far as the OET subtests are concerned. If you think you would crack it without any guidance, you may do so. However, it is always advisable, especially for beginners, to enroll themselves in a proficient coaching centre with substantial experience in training and mentoring the OET aspirants because the experience of a seasoned mentor is insuperable and the atmosphere of a coaching institute is conducive to learning