You’ve probably heard the “rules” of retirement: the 4% rule, the Rule of 72, “multiply your salary by 25.” They sound simple. But are they really good guides for your future — or can they do more harm than good?
Let’s walk through the most common retirement rules, what they mean, and whether you should even pay attention to them.
Retirement Rule – The 4% Rule
This is the most famous retirement rule. It says you can withdraw 4% of your retirement portfolio each year and expect your money to last about 30 years.
- It was created in 1994 by financial planner William Bengen.
- Based on U.S. market history, it worked in many scenarios.
- But today, lifespans are longer, inflation has been higher, and bond yields are different than the 1990s.
Takeaway: It’s a helpful starting point — but not a guarantee.
The Rule of 72 For Retirement Planning
This rule helps you see how compounding works. Divide 72 by your rate of return, and you’ll know how long it takes money to double.
- At 6% return → money doubles in 12 years.
- At 8% return → money doubles in 9 years.
It’s great for showing the power of growth, but real returns bounce up and down every year — so it’s a teaching tool, not a plan.
Other Popular Retirement Planning Rules
- “25× Rule”: Says you need 25 times your annual expenses to retire (built on the 4% rule).
- “7% Rule”: Suggests stocks return 7% long-term. True on average, but averages hide long stretches of poor returns (like the 2000s).
- “20-Year Retirement Rule”: Plans for 20 years of retirement. But half of couples age 65 will see one spouse live beyond 90 — making 30+ years common.
Takeaway: These rules are easy to remember — but oversimplify reality.
Real-World Impact: When Retirement Rules Don’t Match Reality
Consider two retirees:
- Retired in 2000 with $1M: The dot-com crash hit early. Following the 4% rule meant withdrawals during a market downturn. Their portfolio struggled more than expected.
- Retired in 2010 with $1M: Markets rebounded strongly over the next decade. Withdrawals at 4% worked out much better.
Same rule. Same amount. Two completely different outcomes — just because of timing.
Why Retirement Rules Can Mislead
Rules don’t account for:
- Longevity: A couple age 65 has a 50% chance one spouse lives past 90 (SSA data).
- Inflation: Spikes in 2022–23 showed how rising costs can shrink purchasing power quickly.
- Taxes: Withdrawals from different accounts (IRA, Roth, taxable) are taxed differently.
- Health care costs: The average 65-year-old couple may spend $315,000+ on health care in retirement (Fidelity, 2023).
- Personal goals: Rules don’t know if you plan to travel, support kids, or give to charity.
Should You Use Retirement Rules?
Rules of thumb are like a compass: they point north, but they don’t give you the map.
- They’re helpful for quick checks. They give you a ballpark idea.
- They’re risky if followed blindly. They can’t replace a personalized financial plan.
- They’re best used as conversation starters. A rule can spark the right questions — but it’s your personal numbers that provide the answers.
How to Incorporate Retirement Rules into Real Financial Planning
If you want to use rules, here’s how to do it wisely:
- Use them as a baseline. Ask, “What would this rule say for me?”
- Test them against your situation. What if you live longer, spend more, or hit a market downturn?
- Blend them with a plan. Layer in your income sources, tax picture, and health needs.
- Review regularly. Markets, laws, and your life all change. Rules are static. Plans aren’t.
Retirement Rules at a Glance
| Rule | What It Says | Pros | Cons / Limitations |
| 4% Rule | Withdraw 4% annually, portfolio should last ~30 years | Simple benchmark, well-studied | Based on past U.S. returns; may not fit today’s markets |
| Rule of 72 | 72 ÷ return rate = years to double money | Easy way to explain compounding | Ignores volatility and real returns |
| 25× Rule | Save 25× annual expenses to retire | Quick gauge of readiness | Same flaws as 4% rule; oversimplified |
| 7% Rule | Markets return 7% long-term | Shows long-term growth power | Averages hide weak decades |
| 20-Year Rule | Plan for 20 years of retirement | Easy to understand | Underestimates longer lifespans |
Should I Use These Retirement Rules?
Retirement rules of thumb are easy to share, and they help simplify a complex topic. But they’re not enough on their own.
The smarter approach is to use rules as checkpoints — then build a personalized financial plan around your real life: your income, your health, your family, and your goals.
That way, the rules don’t run your retirement. You do. Don’t rely only on the rules to plan your retirement. They can help guide and provide you in the right direction, but the rules alone won’t be able to fully understand your specific scenario.
About the Financial Planning Author
Alexander Langan, J.D, CFBS, serves as the Chief Investment Officer at Langan Financial Group. In this role, he manages investment portfolios, acts as a fiduciary for group retirement plans, and consults with clients regarding their financial goals, risk tolerance, and asset allocation.
With a focus on ERISA Law, Alex graduated cum laude from Widener Commonwealth Law School. He then clerked for the Supreme Court of Pennsylvania and worked in the Legal Office of the Pennsylvania Office of the Budget, where he assisted in directing and advising policy determinations on state and federal tax, administrative law, and contractual issues.
Alex is also passionate about giving back to the community, and has participated in The Foundation of Enhancing Communities’ Emerging Philanthropist Program, volunteers at his church, and serves as a board member of Samara: The Center of Individual & Family Growth. Outside of work and volunteering, Alex enjoys his time with his wife Sarah, and their three children, Rory, Patrick, and Ava.
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