A: Judaism doesn’t mandate having second B Mitzvahs at the age of 83 but there is some logic for having them -- and we have heard of a few such events. The idea behind it all is that, in Psalms, David notes that a man’s normal lifespan is 70 years. Thus, an 83-year-old is technically a 13-year-old in his second lifetime. (As to whether or not he's spry enough to do the limbo at his B Mitzvah party remains to be seen.)
