Sorry if this question has been asked previously and I missed it, but I have always been taught (probably like most people) that a first class medical is good for 6 calender months a second class for 12 calender months etc. Then I was told by an AME that you actually get an extra month because according to 61.23 (2) "A second-class medical certificate expires at the end of the last day of-the twelfth month after the month of the date of examination shown on the certificate..." It seems that this could be interpreted to mean you get an extra month because the end of the twelfth month after the date of exam would be the end of the next month the following year. Furthermore, if the FAA intend for us to go by the 6 calender months or 12 calender months why didn't they just write that? I know that this is an anal question and I am still going to go by the way I was taught previously to be on the safe side, but this topic is sparking a debate at my school with some pretty knowledgable people and I thought I would get some of your views as well. Thanks!