The math, however, is quite daunting. To retire at 35, with an expected mortality of 75, means you have 17 years (age 18 - 35) to earn enough money to support you for 40 years. That's without any higher education. If you attain a post-secondary degree, then that cuts the window down to 13 years (since you'd be in college from 18-22).
Let me clarify a bit...
Our plan started after we were both out of college, had paid off the tiny loans we had ($3000 total, which seemed like a lot back then), both had good jobs, and were about 2-3 years into paying off a modest house that was also dirt cheap (We paid less than $80k and it's worth about $250-300k now with no mortgage). Plus, as you point out later, we were dual-income with no kids or plans for any. We also started with almost $60000 in savings already over 2 years so we had a good idea what was doable.
And the plan was to be able to retire, minimally, by a certain time which turned out to be about 2007. In other words, the original idea was to be able to cover our basic expenses and then work a little to pay for play and luxuries. Without doing the math I'd say that would be about $40,000 in today's dollars. That does not include taxes and investments. Our actual expense now are higher, but not by a factor of 2, and there are things in that number like cable, travel, and dining out that could be cut. I think $40,000 is still a decent target for a minimal retirement (for us). We would work just a little to pay for the extras like cable and travel. Obviously some people live on less, maybe a lot less, and some people would need quite a bit more. But the idea was not to have to sacrifice and we haven't.
I exclude taxes because, though we clearly pay a lot now, much of our savings was after tax, and we churned it to pay the taxes along the way so that our withdrawals will see very low taxes. Of course our retirement plans will be taxed but they will also grow for almost the first 20 years of retirement so that's more than a wash.
So basically, we need $40,000 a year for 40 years. We can take out 2.5% of the principal every year and it will last 40 years with certainty. If we got a return of 5% over that we'd need a little under $500000 and we had about 17 years to accumulate it according to the plan. That meant saving about $27000 per year assuming no growth (return). Between 2 people and including employer contributions to retirement plans, that was not at all unreasonable. It worked out to about a 30% savings rate in the beginning. We both worked in jobs where the employer contributed about 8% of income as a "match." (At the time we had defined benefit plans that we later were able to roll out into IRAs and, in my wife's case, keep the credit for.)
We got lucky with a couple of years of spectacular returns in the 90s and some advantageous changes to our pensions back then. But our plan did nominally succeed and get us to a good place where we had good options to retire or not. I think the key was long term consistency and having a plan. Luck has led to having considerably more than we need at this point but the original plan did not require luck.
A standard Safe Withdrawal Rate is 4%, but that provides a theoretical drawdown period of 30-35 years. You must make it last at least 40, so realistically, you can only withdraw about 3.5% per year. That means you need to accumulate about 25.5 times your income, in assets, in just 13 years.
I think a safe withdrawal rate for early retirees is closer to 3-3.5% depending on how early. In reality though it makes sense (at least for Americans) to follow a different withdrawal plan for tax efficiency and that's what we plan. I suspect you are familiar with this.
I'm going to be honest. The reason I'm being so hard on Billy is not because the math is absurd. It is, but in truth it's not as absurd as I've portrayed here. I've ignored dual-income, no-kid households, inheritances, tax shelters, windfalls, pensions kicking in at 67, living frugally in retirement, and other mitigating factors. It still doesn't make it attainable to the everyman, but it's not completely impossible.
The reason I'm being so hard on Billy is because he's espousing the same brand of "Get Rich Quick" rhetoric that snake-oil MLM shysters use to play on peoples' avarice and indolence to entice them into schemes whose sole purpose is to exploit their naivete and separate them from their money. I despise such programs with a passion, and will shine a bright light on any cockroach that I suspect is trawling these forums for potential victims.
Yes, I agree with what you say about Billy. And he still has not even addressed many of the Ferrari story.
My biggest peeve with the snake-oil MLM folks is that they always try to sell laziness (and sliminess). Our plan worked because we worked hard, put in the effort, worked the extra hours when necessary, did our own yardwork, bought reasonable cars, and so forth. People wanted to employ us because we made worthwhile contributions and benefited them. The whole idea of sitting on my duff being lazy and buying a ferrari does not even appeal to me. And I've met or worked with a few very powerful and wealthy people over the years and almost none of them drove fancy sports cars or wore expensive watches either. (Though a couple of them had their own private jets.)
And, where on the Forbes list of rich people are the MLM folks???