With many retirement plans you can choose when to start receiving benefits and how those benefits are paid.
If you have chosen the "joint survivor" payout option, upon your death, your spouse will continue to receive a monthly benefit for the rest of his or her life. Your benefits begin at the retirement age specified in the plan documents. Your pension plan may allow for early retirement if certain criteria are met.
These plans are called cash balance plans. In these plans (and in some traditional plans) you may choose to receive the benefit all at once as a lump sum (with consent of your spouse) or as an annuity (monthly payment).
Distribution from your 401k must begin by April 1 of the year following the later of (a) the calendar year that you retired or (b) reached age 70 and 1/2.
The best way to know what choices your specific retirement plan offers is the plan's summary plan description or SPD. The SPD describes when participation begins in the plan, how service and benefits are calculated, when benefits become vested, when benefits start and in what form, and how to file a claim for benefits. If you don't have a copy of the SPD, you can request one from the plan administrator.
How you receive your benefits also may have specific tax consequences to consider. For example, if you receive your benefits as a lump sum, you may be subject to higher income tax on the amount unless you take steps to minimize the tax burden such as the possibility of "rolling over" the payout into an IRA or other tax-deferred account within 60 days. Consult your plan administrator and tax or financial planning advisor about these issues.