On one hand, having multiple health insurance policies means having more coverage for medical costs. For people who own insurance through their company, a second health plan makes them more independent. In other words, they don't have to worry about going uninsured should they lose their job and the health insurance that comes with it. On the other hand, having more than one health insurance plan doesn't mean you won't have any out-of-pocket costs. You may still have to pay for any cost-sharing under plan rules (e.g., premiums and deductibles). Another limitation is that the combined coverage cannot exceed 100% of the cost.