The document discusses using Social Security as a form of longevity insurance. It explains that by having the higher earning spouse delay collecting Social Security benefits until age 70, it can maximize the survivor benefit for the remaining spouse. This strategy provides the highest monthly income for the surviving spouse if one of them lives an extremely long life into their 90s or 100s. Even if the higher earner passes away earlier, say at age 70, the surviving spouse would still receive a larger monthly benefit from the delayed collection compared to claiming earlier at age 62. Viewing Social Security in this way helps protect against the risk of outliving one's savings.