There are (at least) 2 different ways to measure how long it took them
1) years since graduating or 1st fulltime job
2) years between defining the FIRE-goal and achieving it
I chose the 1) measurement.
Why did I want to know that?
1) in order to compare
2) in order to have benchmarks
3) just for fun, because I like statistics
4) etc.
So I created a small overview of people who I know through blogs or on this forum. Of course it is not representative. (n=25)
I tried my best to get accurate data. If you find any mistakes, please let me know.
The average time (years since graduating or 1st fulltime job till FIRE'd) is about 12 years.
@jacob: I decided to count the years from 2001 till 2006 (as you describe in your post How I became financially independent in 5 years – Part I).
On the FAQ page you mention, that after "a few years of not working" you "got an offer to work in finance in Chicago.." and "spend just under 4 years working" there before you "stopped working". So maybe those ~3 years could add up to your 5 years till you officially FIRE'd? (for the purpose of this overview)
Maybe you are interested in that. So I share it. If you like to see that spreadsheet, you can find it here: years to FIRE'd
It looks like that