Oh for goodness sake. The conservative assumptions layered on top of conservative assumptions can prevent people from landing on perfectly adequate retirements. I just deleted several paragraphs detailing how (very engineer like) I made such calculations. While my goal was FI, not necessarily ER, when the BS bucket got full I left and now have solid pension I never expected, SS taken at 70, bunch of money because kids got scholarships didn't expect, and IRA/457 that will cost as much in MRD taxes as a frugal couple could retire on. And I'm still looking at the FIDO calculator assuming worst case with a portfolio almost twice when I retired in 2011.
My point is, in retrospect for me and in a lot of posts on this board, I see so much nail biting and conservative assumptions that it can get in the way of achieving goals such as a a pleasant retirement. Which is damn funny coming from me, who has generally followed a pessimistic and financially conservative path. Now I'm trying damn hard to join Robbie and blow some of the bountiful dough that such a philosophy built up. Don't be like me. FWIW, if I were to make a prediction on SS I'd guess FRA might be adjusted and they'd tax it all. As far as I"m concerned...meh.