If you're taking the exam for the first time (i.e., "initial certification"), it will be over 2 days. The first day is all multiple-choice questions (4 sessions, 2 hours each, total = 8 hours) with 100 minutes of allotted breaktime divided over 3 breaks. The second day is a half day of ECGs and images (echo, cath, etc.); this section is not for recertification exams. This is by no means a test that feels longer or harder than all the exams you've taken before. However, I recommend doing the tutorial before exam day to familiarize yourself with the test taking software; it is available on the ABIM website. Unless you have taken tests before with no breaks, and passed, I recommend planning out your breaks and taking them (use the restroom, eat a snack, stretch). You should come back to each session with a fresh mind because the questions/cases can be long. And don't forget, the majority of people pass this test!