Dear Liz: My husband and I are in our 50s and have widowed moms in their 80s. We always understood that when you begin taking Medicare, you are required to choose a plan such as SCAN or Blue Shield and to follow that plan’s benefits and limits. However, my friend who works in a hospital told me that you can elect to have straight Medicare and have no plan limits. Can you explain this?

Answer: What you’re asking about is known as traditional or original Medicare, which consists of two parts. Part A is usually premium-free and covers hospitalization. Part B covers doctor visits and has a standard monthly premium of $148.50.

Traditional Medicare is administered by the federal government and is accepted by the vast majority of medical providers but doesn’t cover everything. For example, beneficiaries must pay deductibles, 20% of Part B services and a portion of hospital stays. For that reason, many people with traditional Medicare also buy supplemental or “Medigap” policies from private insurers to cover these costs. Most Medigap plans, like traditional Medicare itself, don’t have out-of-pocket limits.

By contract, Medicare Advantage plans, also known as Medicare Part C, do have out-of-pocket limits. Medicare Advantage plans are “all in one” coverage provided by a private insurer rather than the government. These plans provide everything covered by Parts A and B of traditional Medicare, and may cover other costs such as vision, hearing and dental that traditional Medicare doesn’t. The plans typically have networks of doctors and other medical providers. If you get care outside that network, you would pay more and sometimes all of the cost.

The final part of Medicare is Part D, prescription drug coverage. That’s purchased from private insurers and may be included in Medicare Advantage plans.

Obviously, Medicare can be complicated, but you can educate yourself at Medicare.gov and download or request the handbook “Medicare & You.”