Don McDonald Reveals the Cash Flow Question That Retirees Must Answer First

Retirement planning centers on replacing incoming money and maintaining a lifestyle for 20 to 30 years. If the replacement question cannot be answered with specific dollar figures, decisions about Social Security timing and portfolio allocation become guesswork. Underestimating required income can cause running out of money in the 80s, while overestimating can lead to working longer than necessary or spending too little while still healthy. A $2 million portfolio has no meaning by itself; the key is whether portfolio income plus Social Security and pensions covers annual spending after inflation for life. In an example with $80,000 annual spending, Social Security covers about $45,000, leaving a $35,000 gap that the portfolio must generate. Using a 4% withdrawal rate requires about $875,000, while a 3.5% rate requires about $1,000,000.

"“How am I going to replace the money that's coming in and maintain my lifestyle for the next 20 or 30 years? That's what planning really is.”"

"If you cannot answer that question with specific dollar figures, every other piece of the plan, from Social Security timing to portfolio allocation, is guesswork. The stakes are concrete. Underestimate the number and you run out of money in your 80s. Overestimate it and you work years longer than necessary, or you live too cheaply while you are still healthy enough to enjoy spending."

"McDonald's framing is correct because retirement planning is fundamentally a cash-flow replacement problem. A $2 million portfolio means nothing in isolation. What matters is whether the income it generates, combined with Social Security and any pensions, covers your actual annual spending after inflation, every year, for as long as you live."

"Say you and a spouse spend $80,000 a year in today's dollars and plan to retire at 65. Social Security replaces some of that. Per Bureau of Economic Analysis data, total Social Security transfer receipts ran at $1,631.2 billion in the first quarter of 2026, and per capita disposable income reached $68,617. For a typical two-earner couple, combined Social Security might cover $45,000 of that $80,000 budget. The gap is $35,000 a year, and that gap is what your portfolio has to produce."

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