Balances compound monthly using the effective monthly rate (1 + annual net return)^1/12 − 1. Deposits occur at the end of each month or year. The taxable comparison taxes positive monthly investment gains at the selected effective tax rate; losses receive no tax credit. This is a simplified tax-drag illustration, not a tax-return simulation. Annual fees reduce the assumed annual return; inflation adjusts purchasing power. A Roth balance is assumed tax-free only for qualified distributions.