After earning the PSM I certification last year, I then decided to pursue the PSPO I. I took and passed the exam, obtaining 73 out of 80 points (minimum to pass is set at 68). I would like to share with you my experience in this short journey hoping that it can be of use for future aspirants.
It was short since I basically prepared two weeks prior the test. I practiced scrum quizes from M. Lapshin (https://mlapshin.com/) and from the scrum.org website until I got a consistent >95% in both. Every simulation was useful in further retaining and understanding concepts and their situational applicability. At the end of the day, it is not only about passing the exam, it is mainly about acquiring new knowledge. It is relevant to note that even though some questions in the real test ressembled the ones displayed in the simulators, some of them (around 25%) were completely new. Before I sat for the exam I was confident I knew everything inside out, but these new questions challenged my self-confidence. Thus, do not get misdirected by very high scores in the simulators because the real test will pose some questions with which you will not be familiar. Therefore, it is a good practice to be prompt answering questions that you know by heart and spend more time to think the answers of the more challenging questions. Bear in mind that you have 60 minutes to answer 80 questions, or 45 seconds per question. In 45 seconds one must read the question, the answers, and think and pick the best answer(s). If you are able to answer an " easy" question in 20 seconds, you then accumulate an extra 25 seconds to answer a more ellaborated and/or unfamilar question.
Even though the test was about the PO, it included several questions about the SM role. Therefore, I would recommend to do a few simulators of PSM I as part of the preparation of PSPO I exam.
In addition, it is important to read well the questions and the answers. Sometimes it is tempting to go fast through questions that we have seen before and are positive we know the answer. This holds true in the majority of cases, but a couple times it happened that I rushed and picked the wrong answer (and of course changed it after a second thorough reading).
Finally, take the test when you are relaxed and not during peak work hours. In my case, Friday afternoon fits very wel. Set your phones on airplane mode, get a glass of water, take a deep breath and start. Hopefully one hour later (or less) you will receive an email saying " Congratulations on passing the PSPO I assessment".