I applied to Duke towards the end of October. File complete on 10/30. Just went under review today. I'm not on the priority track. Does anyone know how long non-PT applicants generally have to wait before hearing back?

I'm preparing to take the test in February, and I have the LSAC book that contains PTs 52-61. I have taken 52, 53, and 54, and I'm scoring very well. Is there a substantial difference between the PTs I've been taking and the most recent PTs? I'm trying to figure out if I should buy more of the recent PTs to take in preparation for the exam.