Making sure you have enough wealth through old age used to be simpler. The idea behind pensions was that your employer would guarantee you a set payout once you retired and handle the investing decisions required to grow the money you would eventually receive. But the pension safety net is full of holes. For one, fewer and fewer employees have access to them: The proportion of private workers covered by them fell from 38% in 1980 to just 20% in 2008. And even if you are lucky enough to have a pension, there's no guarantee you'll actually get the funds at retirement age: That's because unrealistic expectations on investment returns have emptied the reserves of the federal program protecting pensions from losses. With pensions shrinking, the 401(k) has become the preferred investment vehicle of choice: It puts the onus of retirement savings equally on both the employer and employee (assuming matching contributions); and leaves investing decisions to the employer.