This was a great thread to read. Not being any kind of savvy investor and not having exposure to any kind of consideration of the FIRE movement until I stumbled across this forum, I am even more impressed that at 40, even with the luck, that you were able to plan to make such a life saving decision.
For myself, part of the blinders of getting FIREd was the desire to get my pension to a certain level. I never thought of leaving work too early because the idea of a “guaranteed safe retirement” due to the traditional 3 legged steady income streams was almost ingrained and reinforced. I WANTED to retire much younger, especially since my parents actually did FIRE fairly young, (much much younger than I did) though the exact age is not clear because they “relocated to retirement” in Florida in their late 40s, by selling property (developed and undeveloped) that they had bought very young and during lean times, and lived well below their means, having come from basic poverty levels. They bought rental property that needed work there (DF was a builder) and that was their income along with DF taking on building projects flipping a few homes.
Their mistake was underestimating how much inflation would affect their living costs AND their perception that they were “rich” now, and subsequently they never had much of any plan except to let Morgan Stanley generate some income in investments, until they were in their mid 50s, when they sold the rental properties.
This was workable basically by not ever doing anything that cost much and owning their home outright. They never traveled, rarely ate out, my Dad fished, which they ate. This was fine until they both got bored and took up gambling. That predictably was a disaster, ended in divorce in their 60s. DM died at 69 from a lifetime of smoking (COPD) almost broke, but owned her house outright, living entirely on a meager SS, (unfortunately it was during the 2008/9 recession so it sold for only about 10% more than what she paid for it.)
I was in my 40s when much of this drama unfolded so though my “safe” plan meant working until 65, I was ok with that after witnessing such a disaster plus I had 2 divorces under my belt which required me to start all over each time. Luck (ERP and that long bull) allowed me to retire earlier & easily at 61, (DW had retired at 55) with a healthy (in my mind) pension and maintaining the lifestyle with a ton of overseas travel has been easy for the last almost 6 years.