On the other hand, if you live a frugal enough lifestyle that you HAVE a million bucks saved up when you hit 45, and you continue to live that way, it’s theoretically possible, as long as you don’t do anything crazy like have kids, get sick, or whatever.
And certainly not with a 4% drawdown, especially if by that you mean “take 4% this year, then that same amount + inflation next year”.
Maybe if, by “retire early” you mean “quit the rat race, and do something else you love that makes a little money but won’t make you rich”.
Lean FIRE: You don’t work but live like a starving student.
Coast FIRE: The most common. You don’t work and live the same lifestyle as before.
Barista FIRE: You take on a part time job, usually doing something you love, in order to maintain your lifestyle. One guy I met worked in a bicycle shop.
Fat FIRE: Not working and a life of luxury.