I have an academic interest in this topic. My birthday is at the end of August, which puts my half-birthday somewhere in February 29/30/31, so I have a Pirates of Penzance problem here with regard to my eligibility to withdraw from retirement funds without penalty at age 59-1/2.
But not really of course, since I am not really expecting to cut it that close, and will just wait until the following month to be sure.