PPOs have signed contracts for lower fees with a network of health care providers (also called in-network) and they give their policyholders a financial incentive to stay within that network. For example, a visit to an in-network doctor might mean you'd have a $10 co-pay. If you wanted to see an out-of-network doctor, you'd have to pay the entire bill up front and then submit the bill to your insurance company for an 80 percent reimbursement. With a PPO, you can still refer yourself to a specialist without getting approval and, as long as it's an in-network provider, enjoy the same co-pay. Staying within the network means less money coming out of your pocket and less paperwork. Unfortunately, many preventive care services may not be covered under a PPO.