WealthCompass Guides

Good personal-finance decisions usually come down to a few big questions handled well: rent or buy, how to attack debt, whether to refinance, and whether you are on track for retirement. These guides work through each one with the reasoning, not just rules of thumb — including the opportunity costs most calculators ignore. They are educational, not financial advice, and written for people who want to understand the trade-offs before they decide. Read the guide that matches the decision in front of you below, then test your own numbers with the calculators on the home page. For decisions with major tax or legal consequences, always confirm with a qualified professional.

All guides

• Opportunity Cost: The Hidden Variable in Every Financial Decision

  Opportunity cost is the value of the next-best alternative you didn't choose. Most personal finance calculators ignore it, which makes their answers wrong. Here is how to think about it and where it matters most.

• Rent vs Buy: The Real Math

  Rent vs buy is one of the largest financial decisions most people make. It is also one of the most commonly mis-analyzed. Here is the math that actually works.

• Debt Payoff Strategy: Snowball vs Avalanche

  When paying down multiple debts, the order matters. Two main strategies compete: avalanche (mathematically optimal) and snowball (behaviorally optimal). Here is when each wins.

• Retirement Math Fundamentals

  Retirement planning involves a small number of foundational concepts that, once understood, make all the calculators and rules make sense. Here is the math, why the conventional 4% rule has been challenged, and how to think about your own readiness.

• The Power of Compound Interest

  Albert Einstein reportedly called compound interest "the eighth wonder of the world." That may be apocryphal, but the math is real and worth understanding. Here is what compound interest actually does and why time matters more than rate.

• How Much Emergency Fund Do You Really Need?

  The "3-6 months of expenses" rule is a starting point, not an answer. Real emergency fund sizing depends on income stability, dependents, insurance coverage, and risk tolerance. Here is how to calculate yours.