I am 50 and accidentally reached FI at around 35 via a lucky rental property investment, but have only gotten serious about my financial life in the last 4 years or so. When I think of how much money I have frittered away over the years, it is pathetic. I did, however, kill all my debt during my last stint in the working world (I go in and out as needed and as able in a lower-middle-class income range, which is plenty when combined with rental income), and have a decent IRA in place. It is hideous to admit that until the last few years I never even had an emergency fund; I mean NONE. That has changed, thanks to discovering Get Rich Slowly, MMM and other PF blogs. My loved ones roll their eyes, but PF blogs been lifechanging for me.
I'm now quite frugal with stuff like cell phones (Ting), cable (none), cars (older, used, reliable), clothes, food, bike when possible, etc. But I'm also in an educational program that is costing me money (though I'm not incurring debt), and I'm doing it for the love of it, not as a career move. I know that is not frugal, but for personal reasons I felt it was worth it. I also don't own a home but feel overweight in real estate so hesitate to buy more. I sometimes worry about spending my old age under a bridge but I remind myself that while not perfect I am taking steps, slowly but surely, to secure my future.