If money decisions were purely mathematical, personal finance would be easy. Spend less than you earn, invest in low-cost index funds, and let compound interest do its thing. But as anyone who’s ever faced a financial dilemma knows, money is emotional, unpredictable, and deeply personal.
Morgan Housel, in The Psychology of Money, makes a compelling argument: in finance, it’s often more important to be reasonable than to be rational. In theory, rational decisions are always the best ones. But in reality, the best financial strategy is the one you can stick to—not the one that looks perfect on paper.
Take investing, for example. Rationally, the most efficient strategy might be to hold a high percentage of stocks for decades, never check your portfolio, and ride out every market drop without flinching. But most people don’t work that way. Market downturns can make even the most disciplined investors nervous, leading to panic selling. A reasonable approach might involve a more balanced portfolio—one that offers a smoother ride, even if it’s not the most mathematically optimal.
Or consider saving. Rationally, every extra dollar, pound, or Rand should be maximised for return—perhaps going into the highest-yielding investments. But a reasonable approach might involve keeping a larger-than-necessary emergency fund in cash, simply because it provides peace of mind. This may not be the ‘perfect’ financial move, but for many, the ability to sleep soundly at night outweighs an extra fraction of a percent in returns.
The same goes for spending. Rationally, every purchase should be justified by its utility. But life isn’t lived in spreadsheets. If spending a little extra on travel, hobbies, or a quality mattress makes your life meaningfully better, a reasonable approach might allow for these expenses while still maintaining financial security.
This idea extends beyond investing and saving—it applies to financial planning as a whole. A rational person might try to budget every cent to perfection. A reasonable person understands that life is unpredictable and builds in some flexibility. A rational person might chase the highest possible returns. A reasonable person aims for stability and sustainability, knowing that emotional resilience is just as important as financial efficiency.
Ultimately, financial success isn’t about optimising every single decision—it’s about finding a strategy that works for you. A plan that aligns with your personality, risk tolerance, and lifestyle is far more valuable than one that’s perfect in theory but impossible to follow.
So next time you’re making a financial decision, don’t just ask, “What’s the most rational choice?” Ask, “What’s the reasonable choice that I can confidently sustain?” Because when it comes to long-term financial well-being, consistency beats perfection every time.