You are going to retire in 40 years? After retirement, you need $75,000 at the end of the year for 25 years. How much do you have to save for your retirement every month? Assume that you deposit your money at the end of the month for 40 years and 7.5 percent is your annual expected return from investment until you retire. But after you retire you invest in more conservative assets and your annual expected return is 4.5 percent.