Most of us look forward to retirement, imagining that we'll get to relax more and do lots of things that we haven't had sufficient time for -- such as traveling, reading, and exercising. How pleasant and secure our retirements are depends to a great deal on how well we prepare -- and on how many smart moves and how few mistakes we make.It's very risky to leave much of your retirement to chance, as that increases your odds of running out of money long before you run out of breath.