Iv'e been reading posts mentioning Free120/Free150. Is that regarding the sample questions on the USMLE website? For 2017 version there are 117 questions.

I will be taking my exam end of the month so will probably try answering the sample questions in a week or so.

I also saw there are other Free sample questions from 2015 and 2016 that you can download. Are they all the same or do they change the questions every year? Would it be a waste of time to do all of them?

Thanks!