Don't underestimate the importance of choosing the funds in your 401k-your best bet for a comfortable retirement.
Most people are too conservative with their choices.
You should be more conservative with your investments than you were when you were young because you no longer have a long time horizon to reduce your risk. You also need some growth to beat inflation so that the value of your nest egg will not be eroded near the end of your life. The upshot is that you should still own some stocks, but they should make up a smaller portion of your portfolio than they once did. A rule of thumb is that the percentage of stocks in your portfolio should range from 100 minus your age, for conservative investors, to 120 minus your age, for more aggressive investors. The rest should be in bonds.