Horizon length is the single biggest driver of how much $2 million can safely support, more than the size of the number itself. A 65-year-old retiree is typically planning for a 25 to 30 year horizon, which is close to the assumptions behind the traditional 4% rule. A 60-year-old is planning closer to 30 to 35 years, which usually argues for a more conservative starting rate, closer to 3.5%. A 55-year-old is planning for 35 to 40-plus years, which pushes the illustrative safe rate down toward 3% to 3.25% in most planning models. The same $2 million produces roughly $80,000, $70,000, and $60,000 to $65,000 in illustrative first-year income at 65, 60, and 55 respectively, purely from the horizon adjustment, before any other factor is considered.

The bridge years before Medicare and Social Security are where the real cost shows up, and it isn't in the withdrawal rate, it's in the healthcare bill. A couple retiring at 55 or 60 is typically paying full ACA marketplace premiums, often $15,000 to $25,000 a year before subsidies, and managing modified adjusted gross income carefully to qualify for whatever subsidy is available. That healthcare cost, plus the fact that no Social Security check is arriving yet, means the portfolio is funding 100% of the household budget during exactly the years when the withdrawal rate assumption is already at its most conservative.

Sequence of returns risk matters more the earlier you retire, not because the market behaves differently, but because a poor sequence in the first five years compounds across a much longer remaining horizon. A 20% drawdown in year two of a 25-year retirement is a serious but survivable event with adjustment. The same drawdown in year two of a 40-year retirement, with a decade left before any Social Security income arrives to relieve portfolio pressure, is a materially different risk and argues for more cash and short-bond buffer built into the early years specifically.

There is a real advantage that partially offsets the lower sustainable spending number: retiring earlier creates more low-income years before Social Security and before required minimum distributions begin at 73 or 75. Those years, often five to fifteen of them depending on the retirement age and Social Security claiming decision, are frequently the best Roth conversion window a household ever gets, since taxable income is unusually low with no wages, no RMDs, and Social Security not yet claimed. A 55-year-old retiree who uses that decade well can end up with a more tax-efficient lifetime plan than a 65-year-old retiree despite the lower headline sustainable-spending number.

None of these figures are guarantees. They are illustrative planning baselines meant to show the direction and rough magnitude of the difference between retiring at 55, 60, and 65 with the same $2 million, not a projection of what your household will actually experience. The real number for your household depends on your fixed expenses, whether your mortgage is paid off, your specific healthcare bridge cost, any pension or rental income, and how your Social Security claiming decision interacts with the rest of the plan.

The account mix behind the $2 million matters just as much as the total, and often more, at every one of these three ages. $2 million sitting entirely in a pre-tax 401(k) supports meaningfully less after-tax spending than $2 million split across pre-tax, Roth, and taxable brokerage accounts, because every pre-tax dollar still owes ordinary income tax on the way out, while Roth and taxable withdrawals generally don't add nearly as much to the tax bill. Two households with an identical $2 million balance and an identical retirement age can have genuinely different sustainable spending levels once account type and tax diversification are factored in, which is why the same dollar figure isn't really the same plan.

If you're 65 with $2 million, the practical question is usually whether your spending plan fits within a reasonably standard withdrawal rate, since Social Security and Medicare are already doing real work by that age.

If you're 55 or 60 with $2 million, the question is really whether the portfolio can carry the entire bridge years plus a 35-to-40-year horizon, which requires modeling healthcare cost, Social Security timing, and a more conservative withdrawal rate together, not eyeballing a single percentage.

• Using the same 4% withdrawal rate at every retirement age, without adjusting for how much longer a 55-year-old's portfolio has to last than a 65-year-old's.
• Forgetting that a 55 or 60 retirement has no Social Security and no Medicare yet, so the entire early-retirement budget, including a five-figure annual healthcare bill, comes out of the portfolio alone.
• Not modeling how a market drop in the first five years of a 35-to-40-year retirement compounds differently than the same drop five years into a 25-year retirement.
• Treating $2 million as one fixed answer instead of running it against your specific spending, healthcare bridge, and Social Security claiming plan at your actual target age.