Your 401(k) plan is not the type of investment you set and forget. Therefore, as you come closer to your retirement age, you should aim to minimize your risk level. Doing this can help you reduce losses in value in the case of market pullbacks right before you take out your money. If you review your portfolio frequently, this does not involve any extra action.
However, if retirement is just around the corner, you should definitely review your 401(k) allocation and make certain that a big chunk of it has been put in safe investments such as bonds and money market funds.