If you’re about to enroll in Medicare or just need a refresher, here are 10 important terms you should get familiar with. Knowing them can make you a savvier consumer, which means you can choose the best plan for you and get the most from it.

1. Premium – what you pay each month

This is the amount you pay each month to your health plan (whether or not you use care). Private Medicare plans offer a variety of premiums based on the level of the plan’s coverage. Typically, if you pay a high premium, you’ll pay lower costs for care. And if you pay a low premium, you’ll pay higher costs for care.

2. Deductible – what you pay before your plan kicks in

This is the amount you have to pay before your plan helps cover costs. Let’s say you have an annual deductible of $200. Your plan won’t start paying for care until you’ve paid $200 out of your own pocket. Paying for thinks like doctor visits and labs count toward your deductible (your premium doesn’t).

3. Coinsurance and copay – your share of the cost for care

After you’ve reached your deductible, you share the cost of covered services with your Medicare plan. You’ll either pay a coinsurance (usually a percentage of the cost) or copay (a flat dollar amount). Let’s say you need to get an X-ray and it costs $400. If you plan says you owe 20% of the cost for that service, you’d pay $80 and your plan would cover the rest. If your plan says you owe a $15 copay for that service, then you simply pay that $15.

4. Maximum out of pocket – the most you’ll pay for covered services in one year

Unlike Original Medicare, most private Medicare plans limit the amount you’ll pay for covered services each year. Once you’ve hit your plan’s maximum out of pocket, your plan will generally pay all covered services at 100% for the rest of the calendar year.

5. Benefit period – a period of time that your plan and Medicare use to measure your use of hospital and skilled nursing facility (SNF) services

The cost of a hospital stay or a visit to an SNF is often applied per benefit period. A benefit period begins the day you’re admitted in an inpatient hospital or SNF. It ends when you haven’t received inpatient hospital care or care in an SNF for 60 days in a row.

6. Network – health care providers (like doctors, hospitals and pharmacies) that have contracted with your plan

Typically, you’ll get the lowest cost for services when using network providers. This is why it’s important to make sure you use in-network providers for care and other services. In most cases, your prescriptions are only covered if they’re filled at a pharmacy that’s in your plan’s network.

7. Formulary – the list of medicines your plan covers

Wondering if your prescription is covered? Check the plan’s formulary. It’ll tell you if the drug is covered, which tier the drug is in and if there are any special requirements.

8. Preferred cost-sharing pharmacy – a pharmacy that offers a lower price for covered prescription drugs

Preferred cost-sharing pharmacies vary among different Medicare plans.

9. Coverage gap (donut hole) – a Medicare Part D where you’re responsible for more prescription costs

Part D is your Medicare prescription drug coverage. After you and your plan have spent a certain amount of money on prescriptions, there’s a period of time (called the coverage gap) when you’re responsible for more of your prescriptions’ costs. Once you’ve reached your yearly spending limit (which can vary each year), you’ll only pay a small coinsurance or copayment for covered drugs for the rest of the year.

10. Creditable prescription drug coverage – prescription drug coverage that’s as good as Original Medicare’s standards

Original Medicare has a standard for Part D coverage (known as creditable coveragre). The government requires everyone on Medicare to have prescription drug coverage that meets that standard. If you don’t have creditable coverage, you’ll likely get hit with a Part D penalty.