Model assumptions: The baseline reflects your current accounts and contributions as-is — we don't assume you start a new pension or investment. Your existing accounts keep their contributions and growth rates; any leftover monthly surplus stays as cash at 0% growth. Add a scenario to model the upside of starting a pension or investing. Return rates are nominal and applied unchanged — income, expenses, and pension uplifts inflate each year. When the inflation toggle is on, the entire projection (net worth, balances, income, expenses, surplus) is deflated by the inflation rate to display in today's money; the underlying math is unchanged. CGT uses actual cost basis where tracked; 50% gain assumed for older positions. UK state pension uses triple-lock uplift: max(2.5%, inflation) per year.