Dr. David Delnegro MST USMLE Tutor
Just to add on to that excellent responses, I normally tell students to schedule nbmes and UWSAs backwards from your test date. Meaning you’ll want to take the gold standard three (UWSA 1/2) and NBME 18 as your last three in the last 2-3 weeks, kinda like Dan mentioned. This will let you get the best data points when you’re the best prepared.
Further out you can get more creative. If your study plan is longer than the standard 6-7 weeks, I’ll typically say to start with the Kaplan Diagnostic Test so you get some good practice without wasting one of the big gun exams.