For those who have done the PSM3, do you have any advice on knowing if/when you're ready to take it? I took my PSM1 in 2015 and passed with 95%, I just took the exam no formal course (to tick a box for a recruiter). I've just taken the PSM2 now and passed with 90%, no formal course again. I have been on Scrum courses pre my first exam but not since. I have often found myself in the role of coach and teach people in Scrum including Scrum Masters (which I find really makes you think about it).
I am not sure about the PSM3 level in comparison, and honestly, essay questions scare me as I am heavily dyslexic and don't have a good track record with them in general. I am not opposed to going on a formal training course or two (in fact I am very interested in the Scrum with Kanban one but not sure what "level" of course would help me for the PSM3.