When you and your spouse are making this decision, it may be useful for you to focus on three key areas: (1) the out-of-pocket cost of each plan, (2) the levels of service and coverage offered, and (3) the coverage offered to any dependent children, if applicable.

Employers will sometimes pay some or all of their employees' health insurance premiums. If this is true in your case, there may be no reason to consider a change in your health insurance plans. If you pay the premiums yourself, however, compare the costs. Check into whether family coverage through one of the plans is less expensive than two single policies. If you have no children, two single policies are typically less expensive than one policy with family coverage. Many large group plans offer two-person coverage (an employee plus spouse, partner, or child) for less than the price of a family plan. However, insurance carriers will not allow you to bill two companies for the same medical service.

Other important cost factors to consider are out-of-pocket deductibles and co-payments. Even if the premium you pay at your company is lower than that paid by your spouse, you may discover that your deductibles and co-payments for health problems and routine doctor's visits are substantially higher. Despite the higher premiums, you may decide that it is better to join a family plan through your spouse's employer because of its lower deductibles and co-payments.

Be aware that the services and coverage that one plan provides, including the choice of doctors and hospitals, could outweigh the lower costs of the other. You might decide that your family is better off to pay higher premiums, deductibles, or co-payments while receiving specific services (such as rehabilitation, psychiatric therapy, or free eye exams) that the other plan does not offer.