I figured breakeven was about age 84 -- if I lived past 84 I was better off (higher net worth) by delaying taking it. Otherwise I was better off taking it early and investing the early money. (Or actually my heirs are better off in an early croak scenario where I had started taking SS early). Then considering taxes some more, I concluded that the breakeven age for me (and my heirs ) is 81.
One parent died at 81 and the other at 80. There are health factor reasons why I expect the same fate as opposed to living longer according to what the insurance tables say.
My gut extinct was to delay, so I did. To me, waiting for the higher monthly payout was sort of like longevity insurance -- as protection from the economic risk of living a lot longer than expected.
Then I gave my farm away to Population Connection in return for a charitable gift annuity. That totally upended everything: Having higher income in the 6 year window of 2016 - 2021 by taking Social Security would allow me to take a bigger charitable tax deductions for those 6 years (tax deductions for property contributions are limited to 30% of AGI, and only for 6 years).
Anyway, that made what was before a tossup decision into a decision to begin taking ASAP and I ended up beginning taking it at age 65 1/3.
My tax guy was a big believer in taking it early -- besides the breakeven age consideration -- to have the money when you are young enough to enjoy it. That might be a consideration for some, but for me, in the early years, I have enough to do what I want to do even without Social Security income.