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Traditional Retirement Tools Can Derail Your Retirement… And What I Use For My Clients Instead

Traditional Retirement Tools Can Derail Your Retirement… And What I Use For My Clients Instead

By
Jake Skelhorn
February 13, 2025

Introduction

If you've ever engaged in retirement planning or consulted a financial adviser, you may have encountered a Monte Carlo simulation. This tool is commonly used in financial planning to estimate your probability of success—essentially, the likelihood that you won’t run out of money during retirement.

While Monte Carlo simulations serve a purpose, they can also cause unnecessary stress. Instead of providing clear action steps, they often leave retirees anxious about financial uncertainties. In this guide, we’ll break down:

  • What Monte Carlo simulations are and how they work
  • Why traditional probability-of-success scores can be misleading
  • A more practical and modern approach to retirement planning
  • How taxes, market volatility, and spending adjustments impact your financial future

Let’s dive in and bring some clarity to your retirement strategy.

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What is a Monte Carlo Simulation in Retirement Planning?

A Monte Carlo simulation is an advanced financial modeling tool that evaluates your financial future by running 1,000 different scenarios based on historical market performance.

It takes into account:

  • Your age and expected lifespan
  • Your current savings and investment allocations
  • Your expected retirement spending
  • Market volatility and potential investment returns

Unlike a standard retirement calculator, which provides a fixed answer, Monte Carlo simulations generate probabilities of different outcomes. The result is a "probability of success"—the percentage of scenarios where you don’t run out of money before the end of your life.

While this may sound helpful, it comes with a significant flaw: it assumes financial success means never needing to adjust spending. In reality, most retirees naturally adapt to changing financial circumstances.

The Problem with Traditional Monte Carlo Simulations

Let’s consider an example:

Andy is 62 years old and wants to retire now. His plan includes:

  • Spending $5,000 per month in retirement
  • A portfolio of $1.75 million (spread across pre-tax, Roth, and brokerage accounts)
  • A 60/40 stock-to-bond investment strategy

Using a Monte Carlo simulation, Andy’s probability of success is 80%—meaning he has a 20% chance of outliving his savings. While this might sound reasonable, here’s the issue:

  • If Andy needs to reduce spending in later years (say from $5,000/month to $4,500/month), the simulation calls that a failure—even though it's a normal financial adjustment.
  • The score fluctuates constantly due to market volatility without giving Andy clear guidelines on when or how to adjust his spending.
  • It doesn’t tell Andy whether he can increase spending if his investments perform better than expected.

So instead of a "probability of success," a better term might be probability of adjustment.

This is where a more modern approach—Retirement Income Guardrails—comes into play.

A Smarter Approach: Retirement Income Guardrails

Rather than relying on a single probability score, the Guardrails Approach sets clear, actionable thresholds for when to adjust spending.

Here’s how it works:

  • Your financial plan establishes upper and lower guardrails based on your current portfolio value.
  • If your investments decline beyond a certain point, you make a small spending adjustment.
  • If your investments perform well, you may increase spending to maximize your retirement lifestyle.

Example: Applying Guardrails to Andy’s Plan

Using the same $1.75 million portfolio and expected $5,000/month spending, Andy’s plan now includes:

  • A 26% portfolio decline threshold—if his portfolio falls below this, he adjusts spending downward.
  • An upper threshold—if his portfolio grows beyond a set level, he can increase spending and enjoy his retirement more.

This approach provides clarity and confidence because it tells Andy exactly when adjustments are needed—without unnecessary anxiety over every market fluctuation.

The Impact of Taxes on Retirement Planning

Beyond market performance, taxes play a crucial role in retirement success. Traditional Monte Carlo models often overlook key tax considerations, including:

  • Higher future tax rates: If taxes increase, your after-tax withdrawals shrink.
  • Social Security taxation: Up to 85% of Social Security benefits can be taxed if your income exceeds certain thresholds.
  • Required Minimum Distributions (RMDs): At age 73, you must begin withdrawing from tax-deferred accounts like 401(k)s, which could push you into a higher tax bracket.

With a guardrails-based plan, you can:

  • Strategically convert pre-tax funds to Roth IRAs in lower-tax years.
  • Withdraw from different accounts (Roth, pre-tax, and brokerage) to optimize tax efficiency.
  • Plan for potential tax hikes rather than being caught off guard.

Stress Testing Your Retirement Plan

A truly robust retirement strategy doesn’t just plan for the average scenario—it prepares for worst-case events.

With guardrails in place, we can stress test your plan against:

  • A major market downturn (e.g., a 30% drop at retirement)
  • Higher tax rates in the future
  • A Social Security cut of 30%
  • Longer-than-expected life expectancy

For instance, if Andy retires into a bear market, his Monte Carlo probability of success might drop from 80% to 61%—causing undue panic. But with guardrails, he knows exactly how much to adjust spending to stay on track.

On the flip side, if the market performs better than expected, Andy can increase spending—ensuring he enjoys his retirement rather than hoarding money unnecessarily.

Why This Approach Brings Peace of Mind

Unlike traditional Monte Carlo simulations, which generate vague success rates, Retirement Income Guardrails offer clear guidelines:

  • When to cut back if markets drop
  • When to spend more if markets rise
  • How taxes impact withdrawals
  • How to plan for unexpected financial challenges

This proactive approach ensures that retirees maximize their retirement years while avoiding unnecessary stress.

Conclusion: A Smarter Retirement Planning Strategy

Monte Carlo simulations serve a purpose, but they often create more anxiety than clarity. By adopting a guardrails approach, retirees can enjoy financial freedom with:

  • Clear adjustment thresholds instead of vague probability scores
  • Tax-efficient withdrawal strategies that adapt to future changes
  • Confidence in spending decisions throughout retirement

If you’re interested in a personalized retirement income plan, I’d love to help. Schedule a free retirement assessment today by clicking the link below. Let’s ensure your retirement plan is built for long-term success—without the stress.

📌 Schedule Your Free Retirement Assessment

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