No matter when you plan to leave the workforce, one important thing you should know is that your retirement isn't going to pay for itself. Unless you have a pension through your employer (which most workers today don't), you'll need to save aggressively for your golden years.
Enter the 401(k).
A 401(k) is a retirement plan that allows individual employees to save for the future by choosing from a number of different investment options. One benefit of saving in a 401(k) is that once you've set up your plan, the funds you contribute will be deducted automatically from your salary each time you get paid; you won't need to actively transfer money into it or write out checks, as is generally the case with an IRA. And in the large majority of cases when your company sponsors a 401(k) plan, you'll also snag some bonus money cash via an employer match.
Source Fool.com