For generations, the promise of a long life has been packaged as a set of learnable habits — eat well, move often, love deeply. A sweeping review of longevity science now reminds us that reaching one hundred is less a reward for discipline than an outcome shaped by genetics, circumstance, and chance. The research does not diminish the value of healthy living, but it asks us to hold our certainties more humbly: what extends a good life and what carries a person to its outermost edge may be two very different things.