As someone who arrived late to this party, WOW, I must say this thread sure did get interesting, at least based on the Topic, which I have spent some time thinking about.
I am still working so haven't faced the actual question yet, but spend considerable time evangalizing the FIRE concept in a very large office without much success. This group (ER boarders) is an extremely small minority of society, and a fascinating demgraphic to say the least, by far my favorite board on the Internet, and I try to read and contribute to many in my other areas of interest.
I agree with the posters that state that context is essential to giving the best answer, because frankly the reality is so many people just don't "get it". The ER thing is just such a foreign concept. Retirement age to your average Joe is usually 62 or thereabouts, based on that first year of SS eligibility. The more you count back from that, the stranger the idea becomes, until at some point their eyes glaze over, EXCEPT for the fortunate few that do 'get it'.
I work in a place where 10 years early, call it early 50's is very doable for nearly anyone that is motivated, yet hardly anyone does. I am very alone in my plans. Some smile at me, and ask a few questions as to how that can be possible, then realize that it would involve some sort of compromise in their current perceived lifestyle, and quickly decide it is just not possible for reasons that generally don't hold water. OK whatever floats your boat. Work 5 or 10 more years, stay in debt up to your ears, drive those two new cars, get the latest thing that Jones guy has, because your neighbors and friends, and relatives have 'em, and in the case of my coworkers, if their health holds out, they will be fine at 58 or 61 or 65. It will work for them, and they'll just be "retired"
Did they or I contribute to society? You betcha. Our jobs directly effect and improve the lives of others. This branch of this thread leaves me wondering what that has do with the price of rice, but I know in my heart of hearts that the work that I do, and the work that I did made a difference in people's lives and for the better. I just don't see what that has to do with what age I choose to change careers. Isn't ER just a different job after all. Low pay, but very flexible hours? Freedom to pursue other interests?
I don't have to earn a high salary or ANY salary to contribute to society, Do I? My hobbies are Art related. DW and I create glass and silver art and art jewerlry. I enjoy writing and performing music. Do I ever expect to make a dime of either of these endeavours? Nope. I intend to devote just as much time to them as they merit each and every day of ER, anywhere from hours to well, zero. If the thread question comes from someone that I don't know, I expect I'll say I'm and "artist" and see where the conversations goes. Anyone that I'm close to that I think might benefit from by ER diatribe will get both barrels, or until their eyes glaze over. I do think perception matters, and in some circles being preceived as too young to be 'unemployed' would make others uncomfortable. Depending on the situation, we may choose to avoid that effect, then again we may not.