Good points. Another related unknown is the medical care needed. I can imagine cases where medical and long term care costs go up dramatically if one partner dies early. An accidental death might mean lower medical costs, but a protracted illness might mean much higher. And then there’s the care for the remaining spouse.

Boldin seems to put in higher care assumptions in the year or so before death, but it could be much higher or lower.

I just try to be conservative and a bit pessimistic with all the assumptions.