When it comes to investigating Medicare options, many personal financial educators refer individuals to the Medicare.gov website. The official U.S. government website for Medicare is, without question, the most comprehensive of informational portals.

But it can be overwhelming. Especially for the 11,000 men and women who turn 65 every day and first become eligible for Medicare. For most, the terminology is tantamount to learning a new language. Medicare health care plan options are more complex and varied than most are used to.

And, there are some important things the government website doesn’t tell you. For example, it fails to clearly point out the importance of your first plan enrollment. Nowhere on the website does it say that the Medicare plan choice may be irrevocable.

Nor does it really explain what questions to ask before choosing a plan. Medicare.gov does a great job of offering impartial comparisons, such as premium rates. But when it comes to subjective elements, these are something the website can’t obviously address.

Anyone who has been Medicare eligible for a few years will tell you that selecting the right Medicare plan is not easy. In fact, some industry estimates find that between 25 and 40 percent of people switch after making a choice. Navigating the complexity is especially hard when you are first eligible for Medicare. That’s more so if your current or prior healthcare coverage consisted of a few options pre-selected by your employer or trade union.

One of the Medicare.gov features is the appearance of being able to directly connect with an insurance company. And while it’s logical to think that ‘buying directly’ is going to be better and save you money, it’s simply not true. Quite the contrary. It could be a significant and costly mistake.

The following are things to consider when using the Medicare.gov website as shared by the American Association for Medicare Supplement Insurance, national advocacy, and educational organization.

1. Medicare.gov is much easier to use for Medicare Advantage (MA) plans. But that is just one of the options available to you. It may or may not be your best option. For those who prefer to see any doctor or specialist, only a Medigap plan offers that option. For those who travel or spend time in another state, a Medicare Advantage might not cover you outside of your primary area.

2. The Medicare.gov website doesn’t make it easy to understand things that matter such as in-network, out-of-pocket costs, drug plan coverage, coordination with Veteran’s coverage and Medicaid. “In-Network” matters if you decide a Medicare Advantage plan is best for you. Knowing which local doctors, hospitals, and especially specialists participate can be tricky to find on your own.

3. Medicare.gov’s Plan Comparisons seem very detailed. But they miss some important information that’s vital. For example, the decision you make when turning 65 could be irrevocable. Switching Medicare plans is not always possible. Medicare.gov does not tell you what’s possible if you don’t like your choice or when your chosen plan changes. These are all very important things to know before locking in a choice.

4. Medicare.gov’s Plan Finder prescription drug search can be confusing for those taking multiple medications. It’s especially important for the millions who take insulin medications.

5. Medicare.gov lists Medicare Advantage plan ancillary benefits (vision, dental, etc.). Unfortunately, there’s little detail of specifically what’s covered in terms of benefits and service providers.

Buying direct from an insurance company such as UnitedHealthcare (NYSE: UNH), Aetna (NYSE: AET), Cigna (NYSE: CI), or Humana (NYSE: HUM) — several of the leaders – or calling an 800-number may or may not be your best option. Is the person on the other end of the line a captive agent for the particular insurance company? Do they get some incentive for touting one particular plan over another?

Comparing Medicare plan options is always your smartest move. A local Medicare professional who is knowledgeable in local options including Medicare Advantage, Medicare Supplement, and prescription drug plan choices can be a well-spent hour. Today most insurance agents will arrange an online meeting to discuss options and answer questions.

A national online directory listing Medicare insurance agents is offered by the American Association for Medicare Supplement Insurance. Access is free and private, unlike most websites that require you enter information before displaying results. Whether you are turning 65 or just have Medicare insurance questions you want to be answered, it’s a resource worth knowing about.

That local expertise and experience come at no cost. And, the same plans that are available online or available directly from the insurance company can be sold by an agent appointed with the particular company. Perhaps most important, it’s available for the very same cost.

Jesse Slome is the director of several insurance industry organizations that help create awareness for issues related to long-term care insurance planning ( https://www.aaltci.org ) and critical illness insurance ( https://www.criticalillnessinsuranceinfo.org ).