Episode 55 of Wealth Building with Fexingo revisits the famous '4 percent rule' — but not the way you've heard it. Lucas explains how William Bengen's 1994 study was actually about a safe withdrawal *rate*, not a fixed spending plan, and why the rule never accounted for taxes, investment expenses, or variable spending needs. Luna pushes back on the rule's widespread misuse by financial planners, and together they unpack a better framework: the 'guardrails' approach from Jonathan Guyton and William Klinger, which adjusts withdrawals dynamically based on market performance. By the end, you'll understand why a rigid 4 percent withdrawal can fail in the first decade of retirement, and how a simple set of decision rules can keep your portfolio intact through bear markets. No hot takes, just the math and a better strategy.