One of the biggest benefits of an IRA is that it offers access to a virtually unlimited number and type of
investments, giving you
much more control over your retirement savings destiny: You can bargain - shop for low - cost index mutual funds and ETFs instead of being restricted to the offerings in a workplace retirement account, and you can avoid paying the administrative fees that many 401 (k) plans charge.
Forecasting what may most likely happen with these factors
over time (given the assumed fluctuations in the markets - which you can
control every year by using different rates of return on every
investment for every year - including negative rates of return, and being able to change your income goal every year) is
much more important to model, than a one - dimensional probability number, to an actual investor's life.