There are some reasons it is better for working couples to stagger their retirement dates. The reasons are both financial and emotional.
There are three main financial benefits. First, you normally can get more Social Security Benefits if one spouse works longer. Second, the continued income from the working spouse results in additional years of savings for retirement. Third, the additional working time means you draw on retirement for a shorter period of time which allows the retirement assets to continue to earn income and results in a shorter withdrawal period.