Factors to Consider
First, earnings - for a couple, who is a higher earner and who is a lower earner, in terms of social security benefits.
Second, age - who is older and who is younger.
Third, death age - who dies first at what age. To make it more complicated - did the higher earner die first?
Fourth, first claiming age - should the survivor claim right away (assume reaches age 60), or wait later? If wait, should wait till age 66 or age 70?
Fifth, when to switch - if the survivor claims survivor benefits as soon as possible, when should he or she switches to claim her own benefits, at age 66 or wait till age 70?
In short, there are many factors in the consideration, there is not a cookie cutter answer. One thing is for sure, many survivors could be better off by claiming a survivor benefits first, then switch to their own benefits at age 70.