 HMOs often provide preventive care for a lower copayment or for free, in order to keep members from developing a preventable condition that would require a great deal of medical services.When HMOs were coming into existence, indemnity plans often did not cover preventive services, such as immunizations, well-baby checkups, mammograms, or physicals.It is this inclusion of services intended to maintain a member's health that gave the HMO its name.