80 is about right for the break even point. So your own personal health and life expectancy is a big factor. But so is your wife's. if you wait until full retirement age to draw and end up dying before 80 your wife, assuming she survives you, will continue to benefit from the higher monthly payment even though you are gone.
For me and my wife, both of our parents and grandparents and aunts and uncles have tended to live to 85 and beyond with 90's common. So delaying applying for SS benefits made sense for us.
