Is there any valid reason to enroll in Medicare Part B late?

[HipGnosis]

I know there is a penalty charged for enrolling in Medicare Part B late.
Is there any valid reason to do so?

[Rob_bob]

You have employer coverage.

You need to increase your spending I suppose?

Why would you want to delay enrolment, what would you use for comparable coverage?

[Cranky]

I think some people don’t realize that they have to sign up.

But if you still have employer coverage and your employer doesn’t require you to sign up for Part B, you won’t be penalized. Retiring and losing that coverage is a qualifying event and you aren’t penalized.

[Sibley]

You have to sign up, but you can defer the start of coverage. That way you avoid the penalty, but also don't actually have coverage from it. I think you have to have other health insurance though to defer, but could be misremembering.

[dpfromva]

Retired Fed here so my situation is very specific.

I've done a bunch of spreadsheets with various assumptions on insurance cost increase and medical scenarios as I home in on age 65. What I am finding is that if you have a good employer plan in retirement, as I do from the U.S. federal govt, the financial outcome of foregoing Part B, taking the premium you would have paid for Part B and investing instead, seems to be a no-brainer in terms of $ you save/gain.

The monkey wrench is that the benefit shrinks dramatically if you delay taking Part B, due to the 10% annual penalty, so best to decide yea or nay immediately at initial enrollment.

So why do 70% of federal retirees maintain their federal insurance AND enroll in Part B? 1. Government employees tend to be a risk-averse lot (they're not out there running around being entrepreneurs, for example), so they be like "Even MORE insurance I can buy, yay!" 2. You've got the administrative ease of not having to deal with paperwork -- never or hardly ever having to file a claim or pay a bill. 3. As a corollary to 2., if you get a little flaky in your golden years, your kids don't have to help deal with medical paperwork for you.

The only compelling reason for me is that Medicare expands your provider network. If you get some weird disease and want to see the best specialist 3 states away, you're going to save as most physicians remain in the Medicare network. (I looked up stats on that also.)

If I do take Part B, it makes sense to shift to a lower level, less expensive federal employee plan than the Cadillac plan I currently carry. I can experiment with various fed plans at open season every year. Keeping a high level plan and enrolling in Part B seems to really be a double premium hit and waste of $.

Good point above, if you're still employed with insurance, or your spouse is and can add you (which is what we did when my SO retired before I did), there's no penalty, so fine to delay and invest the premium you would otherwise pay.

[Rosy]

Just to add to the Retired Fed Scenario, the Cadillac Plan is the only (Fed) plan that reimburses $600 annually (normally in $50. mo increments throughout the year) if you have Part B.
I discovered that when I reviewed my coverage last year. I got back $600 lump sum for the year prior, which is as far back as they allowed. So I may have missed a couple of years. Serves me right for not staying on top of my coverage.
Since then I get $50 back each month. 

I kept the "Cadillac" Insurance primarily because it also works as Medicare Part D (they send out a confirmation letter to that effect each year) and because I've never had an issue. Claims and paperwork are never an issue and their online setup is great and simple to navigate.
I don't have to worry about coverage if I am out of the country and in-country between Medicare and my own insurance I haven't had to pay a deductible in years.

Mr. R's employer changed insurance a couple of years back. It had not been announced yet but took effect Jan 1. The specialist surgeon he needed for neck surgery he'd worked with since November did not accept the new coverage and so the surgery in Jan was canceled. He ended up waiting in pain for a new surgery date with a different specialist. Sub-optimal.