Use Variable Sweeps

A sweep reveals how one assumption changes the result

Variable Sweeps repeat an analysis across a range of values for one supported input, such as retirement age, Social Security timing, annual spending, planning age, or historical period end year. Holding the rest of the plan constant makes thresholds, flat regions, and tradeoffs easier to see than creating many separate plans by hand.

A sweep is most useful when the values represent genuine choices or credible uncertainty. A wide range of impossible retirement ages or unsupported spending levels may produce a colorful report without improving the decision.

Use a What-if when several things must change together

Choose a sweep when the question is “How sensitive is the plan to this one value?” Use a named What-if when the real alternative changes several connected facts—for example, retiring later may also change salary, contributions, healthcare, pension service, and spending.

Select a range that includes the current value and plausible alternatives. Values close to a threshold deserve neighboring points; a coarse step can make the cutoff appear more precise than the analysis supports.

Run the deterministic view first when the question concerns annual mechanics or a first shortfall. Deterministic sweeps do not use your stochastic analysis allowances; probability sweeps do. Add probability analysis when uncertainty and downside resilience are central.

Review the range before looking for the answer

Choose Retirement age, Annual spending, Social Security start age, Planning age, or Historical end year from the variable bar. In Configure sweep, select Me or Spouse where applicable and review the calculated range before running. Confirm the step and current-plan row. For stochastic sweeps, use consistent model settings and enough trials to avoid treating sample noise as a threshold.

Annual spending tests different annual spending targets. Your spending schedule, including milestones and fixed allocations, scales proportionally from the retirement-year amount; it does not change income sources.

Planning age tests how living to different ages changes your plan. It sets the selected person’s modeled lifespan, not a prediction of death. Unlike the Planning age What-if starter, a sweep tests each age in the range and can shorten or extend that person’s saved lifespan.

Social Security start age tests when benefits begin. Historical period end year identifies each complete historical market window by its final calendar year.

Historical-period sweeps replay specific historical windows and therefore are not combined with a stochastic return model. The purpose is to compare actual sequences under the same plan, not to mix them with newly generated shocks.

Runs per value must be a whole number of at least 10, within the limit displayed for your access level. Commas such as 2,500 are accepted. The workload estimate uses the entered run count and the number of sweep values. Invalid input shows Enter a valid run count and prevents probability analysis until corrected.

Preparation checks the sweep values and their ending balances separately from probability paths. The probability total counts only simulation paths for valid candidates: ten valid values at 2,500 runs each means 25,000 paths. A value with an explained input conflict remains unavailable and contributes no probability paths.

You can leave Variable Sweeps and return to the same variable to check progress or reopen its latest completed report. An unfinished deterministic or probability sweep can recover after an interruption using the plan and assumptions captured when it started. Recovery does not use another daily analysis allowance or change your saved Test Market Uncertainty settings.

Later edits do not change a running sweep. A report based on an earlier plan remains historical evidence; run the sweep again before applying a candidate to your current plan. If the sweep cannot finish, follow its guidance and start a new run when prompted.

For a stuck or unwanted sweep, use Feedback & support. If a sweep is cancelled before completion, no new result is saved. A completed report remains available.

Do not apply a value directly from the most attractive row. First decide whether it is feasible, whether connected assumptions would also change, and whether the neighboring values tell a stable story.

Look for regions and tradeoffs, not a magic point

Find the first shortfall, meaningful improvement, or plateau. Examine several adjacent rows to see whether the outcome changes gradually or flips because of an annual transition. A one-year retirement change can coincide with another benefit or tax event, so inspect Projection before calling the cutoff causal.

Spending sustainability means the modeled plan avoids annual cash shortfall under the sweep’s assumptions. Ending wealth is shown separately from spendable resources because restricted HSA and 529 balances do not serve ordinary spending in the same way.

For a chosen candidate, create or update a What-if with the complete real-world changes and rerun the main reports. The sweep isolates one variable; the plan should describe the actual alternative.

One-variable sensitivity is not global optimization

A sweep does not discover the best combination of retirement age, spending, allocation, benefits, taxes, and behavior. It cannot prove that a selected value is attainable or personally acceptable.

Use it to understand sensitivity and narrow a decision. Preserve practical constraints and connected assumptions in the final What-if rather than adopting the row as a complete plan.

When can I retire?

Open Variable Sweeps, choose Retirement age, then select Me in Configure sweep. The deterministic sweep shows how each tested age changes ending resources; probability analysis applies matching uncertain market paths to every age. Look for the earliest age that meets the success target you intentionally selected, then compare it with the next few ages rather than treating one threshold as exact. When the goal is substantially earlier retirement, people often call the broader approach FIRE—Financial Independence, Retire Early—but YARCalc still tests the saved dates, spending, and resources rather than assigning a FIRE label.

Verify that candidate in Projection and Test Market Uncertainty. Pay special attention to the years between work income and Social Security or pensions, healthcare before Medicare, contribution changes, taxes, early withdrawals, downside balances, and any spending reductions. The candidate age answers the saved plan—not a generic household with the same account total.

A successful row is evidence for a retirement-date conversation, not permission or a guarantee. Revisit the answer after a major balance change, spending decision, job change, benefit estimate, or shift in the planning horizon.

Can I retire at a specific age?

Choose Retirement age in Variable Sweeps, select Me in Configure sweep, and find the requested age in the annual range. Read that row beside the ages immediately before and after it. If the age is earlier than the person’s current age or later than the saved planning horizon, correct the question or the underlying dates before interpreting the report.

For the requested age, compare probability of success, downside outcomes, shortfall timing, bridge withdrawals, healthcare transitions, and ending resources. An age can look workable in a fixed-return projection yet remain fragile when poor early market paths are included.

Use a separate What-if when retiring at that age also changes part-time work, insurance, contributions, a move, or spending. A one-variable sweep should not be asked to represent a life transition with several connected changes.

How much can I safely spend?

Open Variable Sweeps and choose Annual spending. Probability analysis compares calculated spending levels using matching market paths. Find the highest tested level that meets the success target, then review nearby rows and the difference between essential and discretionary spending.

A useful spending answer includes more than success probability. Inspect downside balances, the first shortfall year, modeled reductions, taxes, early-retirement withdrawals, healthcare costs, and the resources remaining late in life. If the suggested level is far from the current budget, verify that the saved budget is complete before changing it.

“Safe” is shorthand for meeting a chosen standard under stated assumptions. It does not mean guaranteed. Use the sweep to define a reasonable range, a baseline budget, and adjustments the household could actually make when results deteriorate.

When should I claim Social Security?

Choose Social Security start age in Variable Sweeps, select Me in Configure sweep, and run Spouse separately when the plan includes a spouse. Start with official benefit estimates and confirm that YARCalc’s claiming-date adjustment is appropriate for the estimate you entered.

Compare the portfolio withdrawals needed while benefits are delayed, taxes after benefits begin, survivor resources, required distributions, and ending balances. For a couple, the strongest individual row may not be the strongest household combination because the larger benefit can affect survivor income.

The sweep identifies financially interesting ages under the saved assumptions. It does not establish eligibility, earnings-history corrections, family-benefit rules, or the final amount the Social Security Administration will pay. Verify a candidate with official records before acting.

What if I live longer than expected?

Create a Planning age What-if and choose a minimum age for each person. The starter extends shorter saved lifespans and does not shorten a person already planned beyond that age. Use a planning-age sweep when the question is how individual ages change results across a range.

Compare later withdrawals, required distributions, Social Security and pensions, survivor filing years, healthcare spending, depletion, and legacy. For couples, a long survivor period can matter more than simply adding the same years to both lives.

A minimum planning age is a stress assumption rather than a prediction. Test more than one horizon when the decision is sensitive to a single late year.

When can my spouse retire?

Open Variable Sweeps, choose Retirement age, and select Spouse in Configure sweep. Check the spouse’s saved birth date, retirement date, income, contributions, and healthcare assumptions before running the comparison. Keep your own retirement date fixed when testing only the spouse’s timing.

Compare nearby ages using the selected success target, shortfall timing, taxes, and remaining resources. Check the working-to-retired transition in Projection, including any change to family healthcare coverage. Use a What-if instead when both people’s work, spending, or coverage must change together.

Test inflation or several changes with the appropriate comparison

Inflation is not a Variable Sweeps choice. To compare general inflation assumptions, create separate What-ifs, change Planning Assumptions, and compare their results under a consistent return basis. Test Market Uncertainty also offers inflation assumptions and supported inflation sensitivities.

Variable Sweeps varies one supported input at a time; it does not provide a two-variable heatmap. Use a What-if for connected changes. For stock and bond mixes, use the retirement allocation comparison in Test Market Uncertainty rather than looking for an allocation variable in the sweep menu.