I used to be obsessed with running our numbers in Firecalc. But at some point, I started using the feature under the "Investigate" tab that - given a time horizon, an asset allocation and a success rate you provide - calculates the withdrawal rate that would have provided you that success rate. I've become much less obsessed with running Firecalc, and only really use it once a year now.
For example:
For a time horizon of 54 years, and an asset allocation of 70/30, I plug in the following inputs under the heading "Given a success rate, determine spending level for a set portfolio..." in the "Investigate" tab:
"Search for settings that will get a success rate of as close to 100% as possible (usually within 1%) by changing Spending Level"
I use a time horizon of 54 years so that I can model a long time horizon but not so long as to exclude the worst start year, which I believe is 1966. We probably won't live 54 more years, but I like being conservative.
I don't bother changing the default portfolio value under the "Start Here" tab as it doesn't matter.
As of this year, these input parameters result in a withdrawal rate of 3.13% at ~100% success rate.
I then calculate what 3.13% of our current portfolio value is to determine where we stand. Happily, my wife and I can maintain a higher standard of living with a 3.13% withdrawal rate. Adding our Social Security and my wife's upcoming pension is just icing on the cake.
While I'm no longer that obsessed with Firecalc, I'm still obsessed with keeping an eye on our numbers, always with a 3.13% withdrawal rate in mind (until next year when it might change).
I'll run this scenario again next year after the next set of market data is included in Firecalc. I'll be using a time horizon of 55 years then.