Financial independence age 40

Hi everyone

I'm pretty sure most of you are familiar with the idea of financial independence. Those interested probably have age goals and plans to achieve independence. Most work on the 4% rule, or safer 3% rule.

I'm sure a few people here might have managed it before the age of 40. I'm curious on advise from those that were able to do it without inheritance. Yes I know you need to start off with a decent salary from the get go, but I'd just like to hear some additional tips or advice. Not interested in the bitcoin millionares story as that amount of luck is a once in a lifetime event.