Dr. David Delnegro MST USMLE Tutor
A good question! I will expand on that in a different post, but the short answer is that First Aid takes a diminished role (in my opinion) for Step 2 CK. Every pass through the material means you should be moving from a higher proportion of passive studying to a higher proportion of active studying.
The first pass (preclinical class) and even the second pass (Step 1) require lots of First Aid typically because so many of the concepts are brand new. The third pass (shelf studying) requires some review to see the algorithms again, but by the fourth pass (CK studying) you should move First Aid from a primary to a secondary resource to look through as needed because you should be cranking through questions at this point.