12 weeks is better. Here are my remarks.
1. Yes, absolutely you will forget material. HOWEVER, you can prevent this by studying in 6 week blocks. On the second 6th weeks do exactly what you would have done if you only had 6 weeks. Your basically starting from scratch or studying for the boards twice. It's like watching a movie. Each time you watch a movie over again, you pick up something else that you didn't see the first time.
2. It allows you to do both Kaplan and USMLE World more thoroughly. If you only had 6 weeks, you would have to rush through 5,300 questions, never having time to process it into long-term memory. With 12 weeks, you can do both.
3. The argument that you peak is a valid one too. But this can be prevented by easy planning. As along as you plan to peak at 12 wks instead of 6, its fine.
4. The idea that "everybody" takes 6 weeks is a faulty one. The boards is essentially a curved test, so if everybody takes 6 weeks, then most likely you also we be like everybody else, and get the same score (unless your super bright) There are only 24 hrs in day, and everybody uses most of them, so you simply just don't have enough time to gain any ground.
5. Another point I want to make is that don't always listen to your Dean's office or professors. When did they take the Boards? If they are like mine, then probably in 1967.
6. Final point: Burnout is mental. Mentally prepare yourself to do it, and you can do it. Otherwise, take a one week break and go to Rio de janeiro.
