Now 62, still working. All TSP acct is from my contributions and matching (did not roll any into TSP from outside.) Never was in the military, so all is from Federal workplace. Now 32 years in FERS/TSP. (I was one of the few nationwide that switched from CSRS to FERS, when the latter came out!)
TSP Balance $880K. Down from my max of 905K in June of 2015. From the start of FERS, I always put as much as allowed into equities (you will recall that when it started it was all G.) Then I did Dollar Cost Averaging with C/S/I when we were allowed to. As the account grew, I started moving $$ around (yes, I was one of the TSP'ers to get "The Letter".)
Tried to stay at 15% contribution most of the time, and a few times was able to sock away the Max (including max catchup). But mostly 15%.
My goal has always been to get to $1MM. Planning to work 1-2 more years, so goal is still achievable.
I encourage all the younger workers to contribute the max possible, as early as possible. Set your goals high! And stick to your plan!