Health insurance is a contract in which an insurer agrees to pay some or all of a policyholder's medical costs in exchange for a recurring premium. Coverage can be obtained through an employer, a government program, or a privately purchased plan, and policies vary widely in how they balance monthly cost against out-of-pocket exposure when care is actually used.
What most separates adequate coverage from poor coverage is the fit between a plan's cost-sharing structure and the policyholder's likely use of care. The key terms to weigh are the premium (what you pay to keep the policy active), the deductible (what you pay before most benefits begin), coinsurance and copays (your share of costs after the deductible), and the out-of-pocket maximum (the cap on what you would spend in a year). Network design, prescription formularies, and whether out-of-network care is covered are equally important, since a low premium can be offset by a narrow provider list.
When comparing plans, model a typical year of expected care, look beyond the premium to total likely cost, and check that your doctors and prescriptions sit inside the plan's network and formulary.
