When it comes to researching Medicare options, many personal financial educators refer people to the Medicare.gov website. The official US government website for Medicare is by far the most comprehensive of the informational portals.

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

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

It also doesn’t really explain what questions to ask before choosing a plan. Medicare.gov does a great job of offering unbiased comparisons, like premium rates. But when it comes to subjective elements, these are something the website obviously cannot address.

Anyone who has been eligible for Medicare for a few years will tell you that selecting the right Medicare plan is not easy. In fact, some industry estimates find that 25 to 40 percent of people switch after making a decision. Navigating the complexity is especially difficult when you are first eligible for Medicare. That’s more if your current or previous health care coverage consisted of some options preselected by your employer or union.

One of the features of Medicare.gov is the appearance of being able to connect directly with an insurance company. And while it makes sense to think that ‘buying direct’ will be better and save you money, it is simply not true. Quite the opposite. It could be a major and costly mistake.

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

1. Medicare.gov is much easier to use for Medicare Advantage (MA) plans. But that’s 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 one Medigap plan offers that option. For those who travel or spend time in another state, Medicare Advantage may not cover you outside of your main area.

2. The Medicare.gov website does not make it easy to understand the important things like in-network, out-of-pocket costs, drug plan coverage, coordination with Veterans and Medicaid coverage. “In-network” is important if you decide that a Medicare Advantage plan is best for you. Knowing which doctors, hospitals, and especially local specialists are involved can be difficult to find on your own.

3. Medicare.gov’s plan comparisons seem very detailed. But they lose important information that is vital. For example, the decision you make when you turn 65 could be irrevocable. It is not always possible to change Medicare plans. Medicare.gov doesn’t tell you what is possible if you don’t like your choice or when your chosen plan changes. These are all very important things to know before selecting an option.

4. Searching for prescription drugs in the Medicare.gov Plan Finder can be confusing for those who take multiple drugs. It is especially important for the millions of people who take insulin.

5. Medicare.gov lists the ancillary benefits of the Medicare Advantage plan (vision, dental, etc.). Unfortunately, there are few details of what is specifically covered in terms of benefits and service providers.

Buy directly from an insurance company such as UnitedHealthcare (NYSE: UNH), Aetna (NYSE: AET), Cigna (NYSE: CI) or Humana (NYSE: HUM) – several of the leaders – or call an 800 number can or can that is not your best option. Is the person on the other end of the line a captive agent for the particular insurance company? Do they get any incentives for promoting one particular plan over another?

Comparing Medicare plan options is always your smartest decision. A local Medicare professional with knowledge of local options, including prescription drug plan options, Medicare Advantage, and Medicare Supplement, can be a good time invested. Today, most insurance agents will host an online meeting to discuss options and answer questions.

The American Medicare Supplement Insurance Association offers a national online directory that lists Medicare insurance agents. Access is free and private, unlike most websites that require you to enter information before displaying results. Whether you’re turning 65 or just have Medicare insurance questions you want answered, it’s a resource worth knowing.

That local experience and knowledge is free. And the same plans that are available online or directly from the insurance company can be sold by an agent designated by the particular company. Perhaps most importantly, it is available for the same cost.