At 90 years old, aging expert and author Katharine Esty has fewer regrets in life — and she's much happier. Her secret? A ...

If you want more happiness in your life, ask yourself this simple question. March 12, 2025 5:00 AM ET. By . Marielle Segarra , Sam Yellowhorse Kesler The key to happiness?

And that also explains why, as natural as change-resistance is, it tends not to improve your happiness. Change in life is inevitable, after all—and always resisting it is onerous.

At 90 years old, aging expert and author Katharine Esty has fewer regrets in life — and she’s much happier. Her secret? A list of nine rules for being happy, healthy and sharp as you age.