Open enrollment only happens once a year, and for most people with Medicare, it’s their only chance to change their plans. As they weigh options, here are some things Medicare beneficiaries should keep in mind:

Part B Premiums May be Increasing for Some People

A report this month in the AARP Bulletin, based on data from the Medicare Board of Trustees, finds that 1 in 7 Medicare beneficiaries could see their Part B premiums increase by as much as 52% next year.

The increase will go into effect if there is no cost-of-living adjustment for Social Security in 2016, but it will apply mainly to those already paying higher premiums because of their income and affect those who pay premiums directly to the government. Most people making direct payments are doing so because they are delaying Social Security benefits, a strategy that can increase future monthly premiums.

Pay Special Attention to Part D Coverage

Although it’s a smart idea to review health insurance options each year, experts say most plans largely stay the same each year. Instead, most people will find changes in Part D plans. Many companies used a claims-based system for determining prescription drug costs and coverage. A medication for which they had a large number of claims may end up moving into a tier with higher copays. However, other insurers may not have had the same number of claims for those drugs, and the out-of-pocket costs for those prescriptions might remain lower in other plans.

The Network May Be More Important Than the Price

Those shopping for a Medicare Advantage plan may gravitate toward the option with the lowest premium. However, there is more than price to consider.

“Patients should be scrutinizing the providers [in a plan’s network],” says Colin LeClair, senior vice president of business and product development for ConcertoHealth, a health care provider for dual-eligible Medicare and Medicaid patients. “The quality of providers is far more important than the cost.”

While it may be hard to gauge the quality of unknown physicians, beneficiaries should at least check a plan’s network to see if their preferred doctors and facilities participate.

65 Year-Olds Need to Enroll Even if They Delay Social Security

Open enrollment is only for those who are already enrolled in Medicare, but now is a good time to remind 65 year-olds that they need to enroll in Medicare, or face penalties. For those filing for Social Security by age 65, enrollment in Medicare is typically automatic. However, those waiting to claim Social Security until a later age will need to be proactive about enrolling. The initial enrollment period runs for seven months and includes the three months before a beneficiary’s birthday, the birthday month, and the three months after it.

Failing to enroll in Medicare during this period results in a 10% increase in Part B premiums for every year you delay enrolling.

The Biggest Change to Medicare is the One You Can’t See

One of the biggest changes coming to Medicare is one that won’t be immediately obvious to patients. Many insurance companies are moving toward outcome-based contracts with providers, which could change how patients are seen by doctors. These contracts are intended to reward physicians who are, for example, successfully managing chronic conditions and reducing hospital admissions.

From a patient perspective, an emphasis on positive outcomes may mean shorter wait times to see a doctor and more time spent with a physician once in the office. Until outcome-based care becomes standard, beneficiaries can use the annual open enrollment period to switch to a new plan with different providers if they are unhappy with their options. However, to make the most of the opportunity, you’ll need to compare more than just price.

U.S. News and World Report: Open Enrollment 2015: What Medicare Beneficiaries Need to Know