Happy story, but I'm also supremely jealous. The thought of retiring after only 35 years of work! That's the outstanding accomplishment here. Either he has a great pension (remember those?) or has been a terrific, disciplined saver over those years. My Boomer parents all had generous pensions and they also retired pretty early. Us younger folks are stuck with crappy 401(k)s that place our futures in the hands of Wall Street and the stock market and other "figure it out yourself" investment vehicles. I feel like this is another ladder that's been pulled up after that generation reached the top.
The number of work years needed before you can retire can entirely be determined by the % of your take-home pay you save. For example, to retire in 35 years (assuming a 0 net-worth), you need to save 21.5% of your money. If you're on HackerNews, you probably have a high enough salary where that's absolutely doable. Bump it up to 35%, and you can knock another decade off of your working career.
This page, like all FIRE stuff, is making rather positive assumptions about the ROI on savings (they’re assuming 5% over inflation). I, for my calculations, am personally assuming 0% growth - I just don’t want to end on a street when I’m 65 or 75.
You have social security which is currently forecast to be funded 73% of current goals (not perfect but not 0 either), and 401(k) averages 7% return over decades, and you have massive quality of life improvements via technology thanks to boomers' collective work.
The lack of pensions suck, but you can get around it. My parents were in good jobs and saved a lot. They were able to retire comfortably and young. Save, more than you can.
Don’t wait. My dad lost a lot of good times due to a medical issue.