Medicare provides insurance for retirees. But while it can help shield you from some of the costs of medical services in your later years, it definitely won't pay for all of the healthcare you're likely to need throughout your retirement. And if you're counting on it to do so, you're going to be in a lot of financial trouble. You don't want that to happen, so you need to be prepared for the realities of Medicare coverage limitations and plan accordingly. 

If you're not sure what kinds of costs to expect, here are five common types of medical services there's a good chance you'll need some time during retirement that Medicare won't help you pay for at all. 

Doctor talking with older male patient.

Image source: Getty Images.

1. Long-term care

Long-term care can cost thousands of dollars per month. While there's coverage for skilled nursing care under very limited circumstances, Medicare won't help you pay for a nursing home or home health aide if you simply get sick or old and need help with routine activities of daily living.

Saving enough for long-term care could be a lifelong prospect, so start early in planning if you can. If you're already nearing retirement or have left the workforce already and don't have time to save for possible future nursing home bills, it's worth looking into long-term care insurance. You could also talk with an estate planning attorney about whether you can make a Medicaid plan to protect your assets while qualifying for this other government insurance that actually does pay for your nursing home or long-term care needs. 

2. Most alternative care

Acupuncture and chiropractic maintenance care are two of the common types of alternative treatments Medicare very rarely helps you foot the bill for. If you rely on these services to help you stay healthy or to manage your aches and pains as you age, you'll most often need to pay for them yourself or make another plan to get them covered.

Some Medigap and Medicare Advantage plans offer at least limited coverage for specific kinds of alternative therapies, so check out your policy options during open enrollment. Signing up for a supplementary Medicare policy or opting for an Advantage Plan instead of traditional Medicare could be your best course of action to get your treatments paid for. 

3. Dental care

Medicare pays for "medically necessary" dental treatments if they're required for you to undergo another covered procedure, such as if you need a root canal before you can get a covered heart surgery. But in most circumstances, you're completely out of luck if you need any kind of dental service -- ranging from a tooth extraction to dentures to a routine cleaning. 

Dental care can cost several thousand dollars if something major goes wrong, so have money set aside for it or consider purchasing an optional dental insurance plan. You can also look for dental schools in your area that may provide discounted services. 

4. Vision care

If you need an eye exam, glasses, or contact lenses, you may be surprised to find Medicare isn't going to help you pay for any of the routine vision care you need. The price tag associated with an eye exam and corrective lenses can be costly, so this is also something you'll need to either prepare to pay for or buy supplementary insurance to cover. 

The good news is, it's often possible to save substantially on eyeglasses or contacts by shopping around online. You may decide it makes more sense to just pay cash for your eye exam and buy discount frames than to buy vision coverage. But do the math to see whether paying insurance premiums or saving up and looking for discounts is the right financial choice for you. 

5. Hearing aids 

Medicare covers neither hearing aids nor the exam necessary to get fitted for one. That can be frustrating if you find yourself unable to hear clearly and facing a big bill to fix the issue. Hearing aids generally cost thousands of dollars, with the price of some advanced devices reaching upwards of $10,000. 

To make sure you can cover these costs if you need help hearing, look into whether a Medicare Advantage plan could be a better fit than traditional Medicare. The VA also provides coverage for hearing aids for eligible veterans, while those who don't have any insurance benefits for hearing aids may be able to save by shopping online. 

The bottom line is, most of these services -- including eyeglasses, hearing aids, and dental care -- aren't optional, and they could eat into your savings if you expect Medicare to cover them and it doesn't. Before you retire, make sure you understand the benefits and limitations of Medicare, shop carefully for coverage, and consider the out-of-pocket costs you need to be prepared for. By doing so, you can avoid facing surprise medical expenses that undermine your retirement security