Originally Posted by WasToldThereWouldBeNoMath
... I know that the vast majority here subscribe to the 100% or bust theory ...
I come at this from a little different angle than most.
Whatever number you get reflects a specific set of parameters evaluated against history. Here is what the FireCalc page says about the future: [FAQ] "How can FIRECalc predict future returns from past performance?" [Answer] "It can't."
So my apostate view is that 90%, 95%, and 100% are all the same number as far as looking forward is concerned.
There is an old joke about economists: "How do you know economists have a sense of humor?" "They use decimal points."
I would suggest a similar joke for retirement calculators: "How do you know that retirement calculator designers have a sense of humor?" "They deliver exact percentages."
If I were to design a calculator, my most optimistic conclusion might be delivered as "You're looking pretty good, but be prepared to adapt as your world changes." and my least optimistic might be something like: "Buddy, you're only looking good in the best of best-case future scenarios. Keep working."