With increasing longevity, retirement is not a single period but a multi-stage journey. Financial plans must distinguish between the early, active "golden years" focused on travel and hobbies, and later years dominated by higher, often unpredictable medical expenses. This requires a more dynamic approach to saving and investing.

In a counterintuitive medical choice, some individuals with healthy but underperforming limbs (e.g., a twisted foot) fight to have them amputated. They recognize that a well-designed modern prosthetic can provide more mobility and a better quality of life than their natural, but chronically dysfunctional, anatomy.

Seemingly harmless jokes and dismissive attitudes about aging are not benign. The World Health Organization found that older adults with negative self-perceptions about their own aging live, on average, 7.5 years less than those with positive views, making the psychological impact of ageism a significant public health hazard.

The book posits that aging is a loss of epigenetic information, not an irreversible degradation of our DNA. Our cells' "software" forgets how to read the "hardware" (DNA) correctly. This suggests aging can be rebooted, much like restoring a computer's operating system.

The tech world is fixated on trivial AI uses while monumental breakthroughs in healthcare go underappreciated. Innovations like CRISPR and GLP-1s can solve systemic problems like chronic disease and rising healthcare costs, offering far greater societal ROI and impact on longevity than current AI chatbots.

A controlled study found that after removing infant mortality, assassinations, and battle deaths, the average Roman male lived 75-80 years. This is comparable to the modern US average, questioning the narrative that modern medicine has dramatically extended our natural lifespan.

The Orphan Drug Act successfully incentivized R&D for rare diseases. A similar policy framework is needed for common, age-related diseases. Despite their massive potential markets, these indications suffer from extremely high failure rates and costs. A new incentive structure could de-risk development and align commercial goals with the enormous societal need for longevity.

A 7-year study of healthy individuals over 85 found minimal genetic differences from their less healthy counterparts. The key to their extreme healthspan appears to be a robust immune system, which is significantly shaped by lifestyle choices, challenging the common narrative about being born with "good genes."

By auditing the "noise" or corruption in a cell's epigenetic settings, scientists can determine a biological age. This "epigenetic clock" is a better indicator of true health than birth date, revealing that a 40-year-old could have the biology of a 30-year-old.