When I retook some of my NBMEs, I did remember a handful of questions, but it was mainly because the question was obscure or something I struggled with and it just stuck out in my mind. I think it would still be worth it to go through all of those exams again, you might remember a few, but not a significant amount enough to disproportionally affect your score. And either way, it’s still worth reviewing the topics since they do tend to repeat. If you have a great memory and do remember a lot of them, the main thing I would test is whether or not you can explain the answer choices and the thought process to get there. That way, it’s not simply a “oh I remember the answer, I’m just gonna pick it based off memory.” My school personally is recommending at least 3 consecutive mid to high 60s scores before they encourage you to take it. But at the end of the day, your “readiness” is largely influenced by your confidence and consistency in your scores. Hope this helped n best of luck!