Firecalc is monte carlo isnt it? I believe so It runs about 100 scenarios, with a standard set of assumptions. I like the program but I don't think it's infallible by any means, especially when your courting scenarios of 10% failure. 9 times you win, but being 85 sick with a failed portfolio would really suck. We have been traveling with very low inflation for a very long time. Regression to the mean would suggest traveling with higher inflation for a long time. Plug 4-5% inflation into firecalc and see how often you fail.