PPO (preferred provider organization) plans offer the most flexibility. Like an EPO, you can self-refer to any provider in the network, without the need to obtain a referral. The main benefit of a PPO, however, is that the plan provides some benefits for out-of-network providers. Some doctors may not accept any health insurance and require cash payment for services. With a PPO, you can see an out-of-network doctor that does not accept your insurance and the health plan will reimburse a portion of the costs. PPO plans typically have the largest network of providers to choose from. If choice and flexibility is important to you, a PPO plan may be the plan for you.