While I always thought I would be able to retire well before I turned 65, several big things happened during my working years to greatly accelerate my path toward ER.
The first was paying off my mortgage in 1998, when I was 35. I used some of the gains from the booming stock market of the mid and late 1990s to pay it off. These were my peak, full-time earnings years, as my pay was rising more quickly than my expenses, increasing my savings rate. With the mortgage paid off, I was able to cover my remaining expenses using only 1 biweekly paycheck per month. The other biweekly paycheck I was able to save, quickly replenishing the money I used to pay off the mortgage.
My company introduced its ESOP (Employee Stock Ownership Program) in 1997. While it grew fairly slowly in those first few years, its value really began to take off in the early 2000s. And in those early years, I was accumulating lots of shares thanks to my peak earnings. So, when its value began to take off in the mid-2000s, I saw the possibility of being able to cash it out while leaving the rest of my separate 401k intact.
Also related to the ESOP was a new tax rule about cashing out company stock. I could use something called NUA (Net Unrealized Appreciation) to pay income taxes at LTCG rates instead of as ordinary income. With nearly all of the stock's value as NUA, this would keep my tax bill pretty low.
Thanks to my expenses being pretty low, I was able to switch to working part-time starting in 2001. This gave me a taste of living on a smaller income amount. It was still more than enough to cover my expenses, only my savings rate fell some. My portfolio's income was rising, so my total income didn't fall by a lot.
In those PT working years, the ESOP was exploding in value. I now saw the chance to cash it out if it reached a certain value, and that value was now on the radar. My existing portfolio was already a good size so the addition of the ESOP being cashed out could provide me with enough investment income if I could find a reasonable bond fund to put it into. I began looking for one with a sufficient return with a risk I could tolerate. I found one.
My next step toward ER was when, in 2007, I reduced my weekly hours worked to 12, from 20. This reduced my income again but it could still cover my expenses. It gave me a little practice for living on a low "income." By this time, I was pretty sure I'd be able to ER by the end of 2008.
Once I found an affordable individual HI policy (no ACA yet), and the ESOP hits its magic number, both in the middle of 2008, I ERed at the end of October at age 45.