Retirement Planning 101

Retirement planning sounds like one problem, but it is really three: saving enough while you work, investing it so it grows, and spending it down so it lasts. This article maps the whole territory so the rest of the Learn section has somewhere to hang.

The three phases of retirement money

1. Accumulation: the working years

During your career, the goal is simple to state and hard to do: spend less than you earn and invest the difference. Three levers control how much you end up with — how much you save, how long it compounds, and what return it earns. Of the three, time is the most powerful and the least appreciated. A dollar invested at 25 has roughly twice as many doubling periods ahead of it as a dollar invested at 45, which is why starting early with modest amounts routinely beats starting late with large ones.

This is also the phase where tax-advantaged accounts do their work. 401(k)s, IRAs, and their cousins shelter your investments from taxes while they grow — the details are in 401(k)s, IRAs, and Other Retirement Accounts.

2. Transition: the years around retirement

Roughly the five years before and after your retirement date are the most fragile stretch of the whole journey. Your savings are at their largest, you are about to stop adding to them, and a deep market drop right here does damage that the same drop twenty years earlier or later would not. This is called sequence-of-returns risk, and it is the single most important idea on this site. It is why many investors shift toward a more balanced stock/bond mix as retirement approaches, and why the retirement date itself deserves flexibility if markets are in crisis.

3. Decumulation: spending it down

Once paychecks stop, the question flips from "how much can I save?" to "how much can I spend?" Withdraw too much and you risk outliving your money; withdraw too little and you spend your retirement poorer than you needed to be. The best-known answer is the 4% rule — withdraw 4% of your starting portfolio in year one, then adjust that dollar amount for inflation every year. Tested against every 30-year retirement start month since 1928 with a 60/40 portfolio, that strategy succeeded 96% of the time with inflation-adjusted withdrawals (and 100% of the time if withdrawals stay fixed in dollar terms, which quietly shrinks your lifestyle). Where that finding comes from — and what it does not promise — is covered in Where the 4% Rule Came From.

The five questions every plan must answer

1. How much will I spend? Not a guess at a far-future budget, but an honest look at what your life costs now and which parts of it (mortgage, commuting, children) will end before retirement while others (healthcare, leisure) grow.
2. What income arrives without my portfolio? Social Security for nearly everyone, pensions for some, part-time work for others. Guaranteed income reduces how much your savings must produce — see Social Security Basics.
3. How big does the portfolio need to be? The gap between spending and guaranteed income, divided by a sustainable withdrawal rate, gives a target. The arithmetic is in How Much Do You Need to Retire?
4. How should it be invested? The stock/bond split drives both growth and volatility, and history has strong opinions about which mixes survived — see Stocks, Bonds, and Asset Allocation.
5. How will I take money out? A withdrawal strategy, chosen deliberately — the options are compared in Withdrawal Strategies Beyond the 4% Rule.

What can go wrong

Most retirement failures trace back to a short list of causes: retiring into a brutal market without flexibility, ignoring inflation (the quiet force that made the 1966 retiree, not the 1929 one, the worst case in U.S. history), underestimating a retirement that can easily run 30+ years, unplanned healthcare costs, and panic-selling at the bottom of a crash. The full rogues' gallery is in Common Retirement Mistakes.

A note on what history can and cannot tell you

Everything on this site is backtesting: replaying strategies through the actual market history of 1928-2021, including the Great Depression, the stagflation of the 1970s, and the 2008 crisis. History is the best evidence available — but it is evidence about the past, not a guarantee about the future. Treat historical success rates as a way to compare strategies and understand risks, not as promises.

Official sources

• Investor.gov — the SEC's plain-language investor education site
• SSA.gov — your earnings record and benefit estimates
• IRS.gov — current-year account rules and limits

This article is educational only and is not financial, investment, tax, or legal advice. Rules and limits change; verify details with official sources or a qualified professional.