There is no universal best age, because the right claim timing depends on health, work status, other income sources, and how much longevity protection you want.
Why waiting can matter
Delaying can increase the monthly benefit, which can matter a lot for households trying to strengthen guaranteed lifetime income.
Why earlier claims still happen
Some people claim earlier because they need income sooner, have health concerns, or simply value earlier access more than a higher later payment.
Bottom line
Claim timing is a retirement-income decision, not just a benefits button to press when eligible.