As you don't have a clock, you need to time it yourself. I allocated 30 minutes to each of the MCQ testlets, and went slowly. When you get a question you don't know, mark it for review later (be honest with yourself on that judgment). Go back once you finish the entire section to review questions if you have time.
I took no breaks on REG, but made sure I re-read questions to try to prevent losing points on “stupid” things. I had about 1-1/2 hours left for my simulations, and my first one was a bear. Lots of calculations, and picking numbers out (and knowing where to put them). I had only 30 minutes left for my second simulation, but it wasn't as voluminous (to me) — but if you didn't know the material, it'd have been a struggle.
If you're running over 30 minutes per section on the MCQ (just a guide — not a firm rule), I'd advise against a break unless it is absolutely necessary. If you leave, you need to check in and check out at the front with Prometrics, and there may be others doing the same. That may result in wasted time, and you want to maximize each minute (if you can).
REG - 97
BEC - 82
FAR - 86
AUD - 96 ... DONE!