Like many of my posts I’m sharing links to excellent advice from other writers.
Ultimately, it may be difficult to forecast your actual income-replacement needs with a great deal of precision. Even as you attempt to anticipate every in-retirement expense to the penny, unforeseen expenditures such as healthcare costs can buffet spending around on a year-to-year basis. But because anticipated income needs are such a key ingredient in the retirement-income puzzle, it’s helpful to come up with as realistic a figure as possible while also being realistic that your own expenditures are apt to vary over time.”
The 7 steps are:
Step 1: Find a Realistic Baseline
Step 2: Subtract Your Savings Rate
Step 3: Subtract Any Tax Reductions
Step 4: Subtract Any Anticipated Housing-Cost Changes
Step 5: Factor in Lifestyle Changes
Step 6: Add Higher Healthcare Costs
Step 7: Add Inflation and a Healthy Fudge Factor
For all the details: https://www.morningstar.com/articles/839519/7-steps-to-estimating-your-in-retirement-cash-flow-needs
Source: Financial Planning for Women