You can't, really. Not in the US. There's no way you can budget health care for that many years.

Yes you can.

1. mrmoneymustache.com 2. earlyretirementextreme.com 3. gocurrycracker.com 4. madfientist.com 5. thepowerofthrift.com (I could go on for a while here)

It's not only perfectly possible, it's not particularly difficult.

No, that doesn't address the problem at all. If you retire thirty years before you qualify for medicare, you have no idea what your medical expenses will be. None. They could amount to millions of dollars over those three decades, depending on your particular issues, and you're never going to close that gap by minimizing expenses.

It does. Just because you aren't comfortable with that risk doesn't mean it's impossible. It just means your risk tolerance is lower than the aforementioned people who did retire 30 years early.

Well, if you're willing to be homeless you can retire any time you'd like.

The amount of people who will actually do this and go through it is so tiny that this comment is worthless. Give and take a few years (and perhaps not in SF/NYC), you could say this about any decent paying job.

Or you'll spend it all on rent?

Why would you do that if your goal is to retire early?

In 10-15 years in SV/NY you can earn $1MM after tax + growth and then move to a lower COL city/town and take it easy.

The problem with that is that your COL in those 10-15 years is significantly impacted. That's probably 10% of your entire life. While I understand some people might be comfortable with the tradeoff... its important to remember there is something you are giving up.

I don't think I understand what you're giving up in that 10% of your life.

I'm living in a studio, have a parking spot, walk to work and go out with my coworkers/friends after work.

What am I missing out on?

After tax? Sure, it's possible, but there aren't actually that many people who make $300k/yr.

$100k after tax is only $140k pretax

Eh... sure, if you're only paying federal taxes. But in on that $140k you're going to end up with about $92k. And everything is more expensive in cities. The idea you're going to live in SF and save more than about half that, even living like a monk, is kind of fanciful.

NYC is even worse - lop another thousand off and pay even more to live.

I've personally lived in both cities and you can live perfectly well on $4k a month with a couple of roommates. Better than the average American even.

Then, if you invest $46k a year for 15 years at a real return of 4% you end up with ~$943k in present day dollars which is right around what the parent was saying.

Not to mention $140k total compensation is relatively low for a senior dev in SF/NYC, you will likely be making a lot more 10 years in.

Where are you going to get a real return of 4%?

US stock market has averaged 8 over the past 50 years

That's unlikely to be true in the future for a whole host of reasons.

You will be making $200k+ in SF even in your early years, if you climb the corporate ladder you can get to $300k in 5 years.

You can definitely sock away enough even without a 4% rate of growth to put away $1MM of after-tax money in 10-15 years, if you're smart with your money.