Health insurance questions answered.

In most states, Open Enrollment runs from November 1 through January 15. Sign up by December 15 and your coverage generally starts January 1; sign up between December 16 and January 15 and it generally starts February 1. Several states run their own marketplace and set their own deadline, some of which run later, so check the dates that apply where you live.

A qualifying life event is a change that opens a Special Enrollment Period outside of Open Enrollment. Common ones are losing other health coverage, moving to a new area with different plans, getting married or divorced, having or adopting a child, and certain changes in income or immigration status. You generally have 60 days from the event to enroll, and you may be asked for documents that prove it happened.

Your Initial Enrollment Period is the seven months around your 65th birthday: the three months before your birthday month, that month, and the three months after. After that, the Annual Enrollment Period runs October 15 through December 7 each year, when you can join, switch, or drop a Medicare Advantage or Part D plan, with changes taking effect January 1. Medicare Advantage Open Enrollment runs January 1 through March 31 for people already in an Advantage plan, and the General Enrollment Period, also January 1 through March 31, is for people who missed signing up for Part A or Part B when they were first eligible.

Yes. Medicaid and the Children Health Insurance Program have no enrollment window, so you can apply in any month. Eligibility is decided by your state agency and depends mostly on household income and household size, and the rules differ from state to state. If you apply and do not qualify, you may be able to enroll in a marketplace plan instead.

Employers set their own annual open enrollment window, usually a few weeks in the fall for coverage starting the next plan year. New hires get an initial window when they become eligible. Outside of those, a qualifying life event opens a special enrollment period, typically 30 days, though you generally have 60 days if you or a dependent lose Medicaid or CHIP coverage or become eligible for premium assistance.

In-network providers have a contract with your insurance company that sets what they can charge for a covered service. When you stay in network, you pay the plan cost sharing and nothing more for covered care. Out of network there is no negotiated rate, the plan may pay a smaller share or nothing at all, and what you pay may not count toward your out-of-pocket maximum. Checking network status before you book is the single easiest way to avoid a surprise bill.

It depends on your plan type. HMO and most POS plans ask you to get a referral from your primary care doctor first, and a visit without one may not be covered. PPO and EPO plans usually let you book a specialist directly. Your plan documents and your member ID card will say which applies, and it is worth confirming before an expensive visit.

Prior authorization is approval from your insurance company before you get certain services, procedures, or drugs. Your doctor office normally submits the request, but the responsibility for making sure it happened falls on you, because a service that needed approval and did not get it can be denied. If a request is denied, you have the right to appeal, and the denial letter has to explain how.

ACA-compliant plans cover a set of preventive services from an in-network provider with no copay, coinsurance, or deductible. That includes many routine screenings, immunizations for children and adults, and well visits. One thing to watch: if a preventive visit turns into diagnosis or treatment, or if a screening is ordered because of symptoms rather than as routine prevention, the visit can be billed as diagnostic care and normal cost sharing applies.

In an emergency, call 911 or go to the nearest emergency room. Plans have to cover emergency services without prior authorization and cannot charge you a higher cost share for going to an out-of-network emergency room. The No Surprises Act also protects you from balance billing for most emergency care and for out-of-network care delivered at an in-network facility, such as an anesthesiologist you did not choose.

Your deductible is what you pay for covered care before the plan starts paying its share. A copay is a flat amount for a specific service, such as an office visit. Coinsurance is a percentage of the cost that you pay after the deductible. The out-of-pocket maximum is the ceiling: once your deductible, copays, and coinsurance for in-network covered care add up to that amount in a plan year, the plan pays 100 percent of covered in-network services for the rest of the year. Premiums do not count toward it.

Not necessarily. The premium is what you pay every month whether or not you use care; the deductible, copays, and coinsurance are what you pay when you do. A plan with a low premium and a high deductible can cost less overall if you rarely see a doctor, and much more if you have a surgery, a hospital stay, or a specialty prescription. Add the yearly premium to the care you realistically expect before you compare.

The premium tax credit lowers what you pay each month for a marketplace plan. Eligibility and the amount depend on your household income, household size, where you live, and the cost of plans in your area. Most people take it in advance so it is applied to the monthly premium. Because it is based on an estimate of your income, you reconcile it when you file your federal return using Form 1095-A, so report income and household changes to the marketplace during the year rather than waiting until tax time.

Cost-sharing reductions are extra savings that lower your deductible, copays, coinsurance, and out-of-pocket maximum. They are separate from the premium tax credit, they depend on your household income, and they apply only if you enroll in a Silver marketplace plan. If your income qualifies you for them, a Silver plan can end up cheaper to use than a Gold plan even though the sticker premium looks higher.

If you receive a premium tax credit and have paid at least one month of premium, marketplace plans give you a three-month grace period before coverage is terminated, though claims in the second and third month may be held. Without a tax credit, the grace period follows your plan contract and state law, and it is usually much shorter. As for bills after a visit, the explanation of benefits your insurer sends is not a bill: it shows what was charged, what the plan paid, and what you owe. Compare it with the bill from the provider, and if the two disagree or the claim was denied, call the number on your member ID card and ask how to appeal.