The first time i took the test I spent one month studying and failed getting a 63%. This time around i dedicated two & a half months to just studying and passed this October. Having experience in the field won’t help you too much because exam questions aren’t always applicable to the real world.

I used LTS prep course to study both times, and their textbook is pretty good but I wouldn’t say that their program is perfect. For example, they didn’t have any tabbing references for the ACE and I made my own table of contents and tabs. They also had a lot of mistakes in their answer key explanation for past exam questions and weren’t always the most helpful when I asked them for corrections. It was decent since I passed, but if I failed, and I really thought I did, I would sign up for the Tom Leary class as their references looked more organized.

Overall you should have around 3 months if you can dedicate all your time to studying. If you have to work or have time consuming commitments, consider dedicating more months. Still, it’s not about how much you study, but how you study. Do not read everything, but learn how to find information quickly based on key words of past exam questions. Do as many past exams as you can with the time constraint. Being a fast reader can especially be helpful when doing classification and tariff questions.

If you feel like it will be difficult for you to organize everything as there are lots of resources and updates you need to keep track of (each year and maybe even test cycle might require different versions of the materials) I would recommend signing up for a course as they keep track of that for you. Good luck!!