So I just got my results back and I passed the MRP exam on my second try. Honestly I was pretty defeated after failing by like 8 points the first time, but I took a step back and completely changed my approach. The first time around I mostly read through the APICS materials and figured that would be enough. It wasn't.
What made the difference was drilling with an MRP practice test almost every day for the last three weeks before my retake. I'm talking 30-40 questions a night, then going back and really understanding why I got things wrong — not just memorizing the right answer. I also used a study guide that broke down the planning calculations and lot sizing logic in plain English, which helped way more than the dense textbook prose.
For anyone prepping right now: don't sleep on the master scheduling and capacity requirements planning sections. They hit those hard. What resources are you all using? Happy to share more specific exam tips if anyone's in the middle of studying.