Millions of seniors get health benefits through Medicare, and while the program does provide access to a wide range of providers throughout the United States, it doesn't necessarily offer the comprehensive coverage enrollees might expect. If you're planning to sign up for Medicare in the not-so-distant future, you should know that you'll have to pay for the following services yourself, since Medicare won't cover them.

1. Dental care

You'd think dental care would be a standard service covered by Medicare, but not so. Routine cleanings, cavity fillings, and dentures are all services you'll need to pay for yourself. The only way Medicare will pay for a dental visit is if the service in question relates to a medical issue, such as needing an oral exam before having surgery.

Smiling woman in white scrubs holding mirror next to older man in dentist's chair


2. Vision exams

Seeing well is important -- it can help seniors avoid accidents and other dire consequences. But Medicare won't pay for you to get your eyes checked, nor will it pay if you need glasses. That said, Medicare will pay to screen for and treat certain eye diseases, like glaucoma. But if your goal in visiting an eye doctor is to ensure that you can see correctly, you're on your own.

3. Hearing aids

Many seniors suffer from hearing loss, but surprisingly, Medicare won't pick up the tab for hearing aids. It will only pay for hearing tests if you're experiencing issues that relate to a specific illness or injury.

4. Long-term care

Long-term care is generally custodial in nature -- meaning, it doesn't relate to a specific medical need or condition, but rather, pertains to assistance with everyday living. Medicare won't pay for care that's custodial in nature, so generally speaking, home health aides, assisted living, and nursing home care are on you to pay for.

Have a backup plan

Clearly, there are numerous services that Medicare won't pay for, and if you're worried about affording them, you have a few options. First, pad your 401(k) or IRA. The more savings you have going into retirement, the easier it'll be to cover these and other health-related expenses.

Next, fund a health savings account, or HSA, if you're eligible to do so. To qualify for an HSA, you must be enrolled in a high-deductible health insurance plan, the definition of which changes from year to year. But if you are eligible, you can contribute money on a pre-tax basis (as is the case with a traditional 401(k) or IRA) and withdraw funds for qualified healthcare expenses tax-free (just like a Roth 401(k) or IRA). And to be clear, HSA funds never expire, so if you put money into an HSA in your 20s or 30s, you can carry it all the way into retirement and use it to pay for the services Medicare won't.

Finally, consider a Medicare Advantage plan over original Medicare. Advantage plans are offered through private insurers and typically cover dental, vision, and hearing services. Some Advantage plans offer some degree of coverage for long-term care, too, though unfortunately, this is largely an expense that seniors have to absorb themselves.

If you're gearing up to enroll in Medicare, it pays to read up on the services it will and won't cover. You should also dig around to see what your costs might look like under Medicare. Having that information will help you better plan for your senior years and avoid the financial stress so many retirees face.