Don't pretend you'll never age.  Give yourself and your family the gift of planning for it.

The answer is yes for most people — but there is an important exception:  This exception pertains to those who contribute to an HSA (Health Savings Account).  The IRS prohibits HSA contributions once you are enrolled in any part of Medicare.  That includes if you are enrolled in Part A only.  Therefore If you are contributing to an HSA, then you either need to NOT sign up for Part A, or stop contributing to your HSA  (IRS Publication 969).   As long as you are an ACTIVE employee, on an ACTIVE employer plan with over 20 employees, there is no penalty for delayed Part A or Part B enrollment.

Keep in mind, when you sign up for Part A, that Part A effective date is backdated 6 months, but to no sooner than your 65th birth month.  Many people get caught off-guard with that 6 month backdating and end up with a tax penalty if they are contributing to an HSA.    Medicare does not prohibit you from having a HSA,  You can keep your existing HSA and use the money after enrolling in Medicare.  The issue is CONTRIBUTING while you are enrolled in Medicare.

That's great that you know about IRMAA!    The acronym IRMAA stands for "Income Related Monthly Adjustment Amount."  Social Security looks back 2 years to your Modified Adjusted Gross Income on your IRS return to determine what you will pay for Part B, and that 2-year lookback will take place every year for the rest of your life once you enroll in Medicare Part B. The chart at the end of this section shows the Part B premium amount by gross income.   In most cases you will not be subject to IRMAA charges, unless you are a high earner AND you enroll in Medicare Part B before you retire.    Follow along with the following scenarios:

Scenario One: You are still working and on an employer health insurance plan with a company that has over 20 employees, and you stay with that your employer insurance until the day you retire.   Now you are ready to retire and enroll in Part B.  Social Security does their 2 year lookback, and let's say your IRS return shows $120,000 as your Modified Adjusted Gross Income.  The standard Part B premium applies to income $109,000 and under, so at $120,000 in income, yes, you would be subject to an IRMAA surcharge.  However, you can appeal that.  Again, assuming the majority of your gross income is from employment, you will have a successful appeal to reverse the IRMAA charge. The appeal is essentially: "I retired. I don't make that much money anymore." Filing that appeal is a quick and easy form.  The key issue here is that you retired, and the majority of your income before retirement was from employment.

Scenario Two:  You decide to leave your employer insurance and enroll in  Medicare BEFORE you retire. Social Security will look to your IRS return from 2 years prior. In this case at a gross income of $120,000 on the lookback.  Since you have not retired, so you will not be able to use that appeal.

Scenario Three:  Let's say your current and past gross income has been in the $75,000 range.  That's under the $109,000 filing single (or $218,000 filing jointly) bracket.   Assuming again your income is primarily from employment income, then IRMAA is a non-issue.  You don't need to worry about IRMAA at all!   Just bear in mind that other financial moves can bump up your gross income — things like converting a traditional 401k to a Roth, rental income, selling an investment property, or having capital gains from the sale of stock.  If you know you will be under the first bracket of the IRMAA surcharge, it is often a good idea to apply for Part B and go on Medicare a few months before you retire for a stress-free transition to Medicare.  Click the SSA-44 link belwo to learn more about IRMAA and review the gross income brackets for Part B premiums.

Short answer: No, don't go on COBRA if you are over age 65.  The exception might be if you are providing group insurance for others in your family who are under age 65.   It's important to understand that COBRA works completely differently once you are over 65:   It pays second to Medicare. That means Medicare pays 80% first — and if you don't have Medicare Part B, you would be personally responsible for that 80%. Then COBRA would pay, at most, the remaining 20%.  Who pays first or second is dictated by insurance law.  This information is provided by employers, but because Cobra is so expensive, many just don't understand that the coverage is so limited because it just doesn't seem to make sense.  Again, some families need to go on Cobra because there are other family members on their health plan and they are between jobs.  But please do not be guard off-guard with a huge medical bill if you are over age 65 and on Cobra.  You will need to enroll and pay for Part B, so Medicare will pick up that first 80% of costs.  Therefore, if you are only covering yourself, and perhaps another person over age 65,  it will make more sense to skip Cobra, enroll in Part B and get a private Medicare plan to work with your Part B.

Companies are required by law to offer COBRA, and it might make sense to keep COBRA for dental and vision — but heed their warning about using it for medical coverage if you are over age 65.

Finally.....Sometimes in casual conversation I will cringe when I hear well-meaning friends or co-workers provide completely inaccurate advice about Medicare.  Medicare is similar to the IRS: nothing is cut and dry.  It's more like, "If this happens… than that… but for when this takes place..... except when it's a Tuesday!   It can seem  a bit convoluted, but there is usually some logic behind all the if/thens!  The medicare.gov website provides an excellent search tool, and is the most reliable source of information about Medicare.  For those of you who are still working and on an employer plan, I highly recommend you take 5 minutes to read through the section "Working past age 65."