I had a general thought recently that might be interesting to folks here.
I'm about 3 years into my career and have been following the MMM 60%ish savings program for a couple years now. During this time, I have found a few coworkers who are similarly inclined, a couple even MMM readers. I am currently exploring a return to graduate school, and one of these friends asked how that fit into the whole FI picture. I had been thinking about that myself and pointed out that between house hacking, getting rid of a car on campus, etc. that I probably wouldn't even come out that far behind my current approach...
However, beyond that, I think I've realized that FI doesn't really say much of anything about whether you have to stay on a traditional career path or even when you retire. I think that, at base, we're simply talking about an attitude toward money and that opening up early retirement is just one of the benefits. Living on a graduate student's stipend or taking time to earn a lower wage AT ANY POINT (not just at full FI) is another option that is open to you with this attitude. A 'mandatory' working career of 10-15 years (time needed to amass the capital), arranged without gaps or in chunks, is just hugely liberating when you have 40+ years of possible working years in which to do these 10-15 years of capital accumulation.
This may be obvious to everyone else, but I was just really appreciating for the first time that I am feeling free to make a choice that I totally would have not felt free to make had I not stacked up X dollars over the last couple of years and learned to be mindful regarding my expenses. This truly is a lifestyle at base, not some formula to work X years and stop. Very liberating.