Social Security is often discussed as a break-even calculation: file early and collect smaller payments for longer, or wait and collect larger ones for less time. That framing is not wrong, but it is narrow, and it leaves out most of what makes the decision consequential.
The benefit is adjusted for inflation and continues for life. For many households it is the only income with both of those characteristics, which makes it less like an investment decision and more like deciding how much of your retirement you want insulated from two risks you cannot control.
Marital status changes the arithmetic. When one spouse has a substantially larger benefit, that amount may continue for whichever spouse lives longer. The claiming decision is therefore rarely about one person in isolation.
Filing also interacts with taxes. Benefits can become partly taxable depending on your other income, and the years before you file are often the years when you have the most control over what that other income looks like.
And health matters, though not in the way people expect. Your own life expectancy is only part of it; the longer-lived spouse tends to be the one the decision follows.
There is no single right age. There is a right age given a particular set of circumstances, and the circumstances are worth mapping before the paperwork.
