This playbook walks you from an empty workspace to a fully run simulation. Each step is small on purpose. Don't worry about getting the numbers perfect on the first pass. You can refine them once you see the Proof view come to life.

You do not have to remember any of this. The first time you open an empty plan, a plan checklist slides out over the left sidebar listing the same six tasks as the steps below, and each row takes you straight to the input it is about. You can reopen it any time from the Plan checklist button at the top of the sidebar, just above Home. Any row that is stopping the plan from running turns red, opens itself, and says why, with a button that goes to the exact field that fixes it. The rest stay collapsed behind a chevron until you want them. The steps here are that checklist, written out.

1. Add a Person

Open the People step and add yourself. The birth year drives every age-gated rule the engine uses (early-withdrawal penalties, RMDs, Social Security claiming windows, Medicare). For couples, add a second person.

Next: People tab reference

2. Add a Brokerage and a tax-deferred account

Move to the Accounts step. Add at least one Brokerage Account — this is required, because it is the only account type that can absorb post-tax surplus into your target asset allocation without a contribution cap. Then add a tax-deferred account like a 401k or Traditional IRA. For each, fill in a balance and an asset allocation across stocks, bonds, and cash.

Next: Accounts tab reference

3. Set your retirement year and final year

Open the Parameters step and fill in the Years card. Both fields start blank on a new plan and both are required, because almost everything else is anchored to them: Retirement Year is when retirement spending begins and what every “at retirement” timing option resolves to, and Final Year is the last year the plan runs through. Each option in the pickers shows everyone's age in that year, so you can choose by age rather than by arithmetic.

Next: Parameters reference

4. Set base spending in the Spending Plan

Move to the Expenses step. Base Living Expenses is shown as a list of time periods: one row per stretch of years, each with its own year range, a label saying whether those years are working years or retirement, and the rule and amount that govern them.

If you're already retired, that's a single row covering the whole plan. If your retirement year is still ahead, you see two rows: a Retirement row for the plan you entered, and above it an amber Working years row for this year through the year before you retire. Until you give those years a period of their own, that row reads "Not set" and the plan spends nothing before retirement. Click it and the period is created and opened for you to edit; click any row to edit that period.

Base Living Expenses (the retirement number)

The Retirement row is always there. It represents your steady-state yearly spending once you're in retirement, and it runs from your retirement year through the end of the simulation. Click the row to open the Spending Plan editor.

The simplest starting point is Inflation Adjusted Spending: enter a yearly amount and the engine inflates it every year using your CPI assumption. You can switch to VPW, Guyton-Klinger, CAPE, or one of the other rules later. They all need a base number first, and the rule choice is what drives whether spending is steady, market-reactive, or portfolio-percentage-based.

Want a different amount at 60 than at 80? Press Add time period inside that editor and split the plan into as many periods as you like. Each one becomes its own row in the Expenses list, with its own rule, amount, floor and ceiling. See spending plan rules for the details.

Your working-years period

If your retirement year is in the future, clicking the Working years row in the Expenses list creates the period, and the editor also offers Add a working-years period. Either way you get a period covering today through the year before you retire. It is worth setting: working-years spending usually looks different from retirement spending, and until you add the period this plan describes your retirement spending only.

The new period is seeded from the retirement one, so all you have to change is the amount. It carries the same controls as any other period: a rule (Inflation Adjusted to track CPI, Not Inflation-Adjusted to hold the dollar amount flat, or a custom growth rate for lifestyle creep above CPI), an amount, and an optional floor and ceiling.

During the working years, the engine will try to cover this spending out of any income you've added (a Job, Take-Home Salary, or other income adjustment). If that income falls short, or you haven't added any, the difference is pulled from your accounts, which can quietly drain your starting balance before retirement even begins. The Expenses list warns you when a working-years period has no income beside it, and Plan Diagnostics will flag it on the Proof view.

Next: Spending plan rules at a glance

5. Review income

On the Income step, add whatever money comes in. For most first passes that is a Social Security adjustment: pick the person it belongs to, set the claiming age, and enter the projected benefit. The engine starts the income flow at that age and inflates it each year. Add a Job or a pension too if you are still working.

Income is not required. If you would rather leave it for later, the checklist row offers No income for this first pass, which marks the task reviewed without adding anything — and asks again the moment you do add an income row.

Next: Income types reference

6. Choose what happens to leftover cash

On the Cash Flow step, set the Leftover cash dropdown. A new plan starts with no choice made and the run stays blocked until you pick one, because the two answers model very different households: Save to brokerage invests every surplus dollar, while Spend it treats the surplus as discretionary spending that leaves the plan. There is deliberately no silent default.

Ordering individual Cash Flow Priorities underneath it is optional — you can come back to that once you have a first result.

Next: Cash Flow Priorities reference

7. Hit Run

With the inputs in place, click Run at the end of the step rail, or click Proof in the sidebar. The engine plays your portfolio against every available historical cycle (1871 onward) and aggregates the results. First runs typically complete in a few seconds.

If Run is greyed out, the Plan checklist button at the top of the sidebar turns red. Click it: every row that is blocking the run is marked Attention, with a button that takes you to the field that fixes it. The count climbs as you resolve them, and Run comes back on once nothing is blocking. When the last row goes green the sidebar button retires and the checklist moves to the Inputs screen, beside Help for this tab.

Next: Proof cheat sheet

8. Read about the success rate

The big number on the Proof view is your success rate: the share of historical cycles in which your portfolio survived to the end of the plan. 95% means 95 out of 100 historical paths made it. 95% also means that in 5% of the historical paths, you would have had to change your plans for your portfolio to survive. I don't always like to frame that 5% as failure, because history is yours for the making.

Next: What success rate means

9. Open the year-by-year analysis

On the Proof view, click Analyze Year-by-year data to open the year-by-year modal. This is where you can step through any single year of any single historical cycle and see exactly what the engine did.

Two sliders at the top of the modal control which year you're looking at:

• Cycle slider. Picks which historical cycle to inspect. Each cycle is one full run of your plan against a different starting year of market history (1871, 1872, and so on). Drag the slider and the panels below re-render against that cycle's returns and inflation.
• Simulation Year slider. Picks which year inside the selected cycle. The label shows the absolute calendar year and each person's age at that point, so you can quickly find a milestone (the year you retire, the year Social Security kicks in, the year an RMD starts).

With both sliders set, the Year Analysis tab gives you two side-by-side panels:

• Allocation. The donut of stocks / bonds / cash for that year, plus a tax bracket progress bar showing how much taxable income you generated and which federal bracket the last dollar landed in.
• Events. The per-year waterfall: incomes received (Social Security, pensions, jobs, payroll detail), spending applied, real-estate cash flow (taxes, insurance, maintenance, mortgage payments), withdrawals from each account, taxes paid, ACA subsidy breakdowns when applicable, and any cash deposits or transfers between accounts. If you've modeled real-estate purchases or 1031 exchanges, those show as their own banner cards.

A third panel, Bucket Strategy, only appears when your spending plan is Bucket Strategy; it shows that year's bucket-decision events.

The second tab, Account Details, is a per-account ledger view of every transaction in the selected cycle. It's a Pro feature. You can ignore it on a first pass.

Next: How a simulated year flows