I've not been working since the end of 2016, so what does that cost? I keep a record of our costs and publish a summary of our spend monthly that shows how much we spend analysed into different categories.
There are some expensive months, and hopefully some cheaper ones too. We're not lean FIRE but not Fat FIRE either, somewhere in the middle, a happy medium I feel.
While each person's lifestyle and expenditure will be different, it gives an idea of costs, and because it is broken down by category, you can always make adjustments for areas where you think your lifestyle and spend will be a bit more or a bit less than mine.
And if you want to ask any questions, please feel free to ask.