I read all 181 posts on TMND thread after it closed. Wow! Lots of interesting thoughts. I sensed an underlying premise in some of the hypothetical calculations/assumptions. One of those was the median income assumption over a 40 year period. I don't know about the rest of you but I started working (a paper route) 38 years ago. My last pay check (January 2015) was just a bit higher than that first one. My first monthly check in the military in 1990 was less than $900. My last check when I retired from the military in 2013 was close to $7500/mo. My point is that since we all started our road to FIRE I would be willing to guess that the vast majority of us received some sort of raises and increased job responsibility. So yes, many can't save much when they start off in their 20's. But, if you find yourself in your mid to late 40's and you are still not saving much for retirement then maybe you weren't trying (or you had that horrible divorce/health issue). My personal experience is that most people don't really try.