Re: Firecalc success rate.
Our own planning is based on a 100% SWR, which will still provide a very nice but not extravagent lifestyle. Since the calculator looks at history instead of the future, even 100% is not totally safe. But using the 100% rate decreases the odds that we will need to cut spending some time in the future.
Like most financial predictions, the only time you know for sure that you were sufficiently careful, is the day you die!