Personal Finance Perspectives for Marketplace Story

How much money is enough? Hi there! I'm a journalist with the public radio program Marketplace. I'm working on a story about the question: "how much money is enough"? It's a bit abstract, but would love to hear how you think about it. Is it a specific number? A feeling? The moment when you no longer have to check your bank account every day? Has your answer changed as your life has changed? Very curious!