What if, and ways to improve your chances

Two screens help you explore changes. What if lets you move the dials yourself. Ways to improve your chances tests a list of common changes for you and ranks them.

What if

Changes on this screen don't touch your plan. Save any combination you like as a scenario. The tabs:

• Quick changes. Sliders for retirement age, spending, savings, returns and other key inputs, with results as you move them.
• What matters most. Shows which inputs move your results the most, by testing each one up and down.
• Two at once. A grid that varies two inputs together, such as retirement age and spending.
• How much can I spend. Finds the spending level that reaches a chance of success you choose.
• The fifth tab compares retirement dates, to show when retiring works out well.
• Life events. Shows how a big event changes your chance of success, such as having children or buying a home. See Life events.

Choose Reset to clear your changes, or Save as a scenario to keep them.

Life events

Pick an event and describe it: when it happens and what it costs. Every amount starts at an assumption marked "using a default". Change it to your own figure. Amounts are in today's dollars and grow with inflation.

Each event becomes real changes to a copy of your plan:

• Have children. Each child joins your household, so the child tax credit and other rules for dependents apply. Childcare, everyday costs by age, and college (with an optional 529) are added as spending. A parent's leave or reduced hours lowers their pay for the months you choose.
• Buy a car. Pay from savings or with a loan. A trade-in lowers what you pay, and you can replace the car every few years.
• Buy a home. A mortgage, closing costs, property tax, insurance and upkeep. You can sell the home you own, at a price you set or at its projected value, or stop paying rent.
• Other events. A wedding, a big trip or a gift is a one-time cost. Caring for a parent is a monthly cost for some years. A sabbatical or career break stops pay for some months. Use Another cost or Another change in pay for anything else.

Three views compare your plan with and without the event:

• Whether. Your chance of success with and without it, how much you could safely spend each month, and your net worth late in the plan.
• When. Your chance of success if the event starts in each of the next 5, 10 or 15 years. The years with the highest and lowest chance are marked.
• How much (or How many, for children). Your chance of success at several amounts. Below it, a grid shows timing and amount together. Each cell shows the chance and the change in points from your plan without the event. Select a cell, or move between cells with the arrow keys, to compare it with the event as you entered it.

Every result uses the same simulated markets as your plan without the event, so a difference comes from the event, not from luck. Each choice is tested on 250 simulated markets. Tick More precise to use 500. Results are kept on this device, so returning to a choice you already tried is instant.

When you're happy with it, choose Add to my plan (you can undo it) or Save as a scenario to compare it on the Scenarios screen. You can also open Life events from Can I afford it? and from the milestones on the Plan screen.

Ways to improve your chances

This screen tests changes that apply to your plan, each on the same simulated markets as your plan. Because every change faces the same futures, differences come from the change, not from luck.

The cards:

• Your chance of success now. Your starting point.
• Smallest change to reach your goal. Pick a target of 80%, 85%, 90% or 95%. The app searches for the smallest delay in retirement, increase in savings or cut in spending that reaches it.
• Changes ranked by how much they help. Each result shows your chance of success with and without the change, the difference, a margin of error, and how ending net worth changes.
• Little or no clear change. Changes whose effect is smaller than their margin of error.
• How these are worked out. The method in brief.

Changes tested include:

• retiring later, saving more or spending less
• claiming Social Security later
• Roth conversions or a different withdrawal order
• spending guardrails
• moving to a state with no income tax
• selling or downsizing property
• lowering fees or changing your stock share

Only changes that fit your plan appear.

These are tests of your plan, not recommendations. See how improvements are tested.