The median Mustachian apparently spends 20-30k per person.
...
That's disappointingly high. :)
I was pretty surprised too. I think people are maybe not all responding as the question asked. Some don't see it's per person. Some may be including mortgage and other loan principal. Some may be including taxes.
We outlay $55K for our household of three at the moment (in disappointingly high territory). Nearly half of that is rent and childcare (and we have REALLY cheap rent for our city). When we're FIRE, our budget will be $35K for the household, so less than $12K per person. One number doesn't really tell much of the story since there are so many variables.
Ohhh...childcare is a good point that could cause serious differences that I hadn't thought of. A family with two young children and two working parents can spend $2k a mo in childcare in some areas, adding $24k a year! This would seriously impact reported spending (eg., ours would almost double from this). Although, their incomes might more than make up for this spending and still make it very worth it compared to a SAHP.
However, a family with a SAHP could have a much lower spending number, although they may still ultimately save less, but possibly the same need in retirement if they have otherwise similar spending (assuming childcare is no longer in the budget for either).
Similar goes for people living in a high COL to earn more and save more. They could have much higher spending than someone living rurally, but they may still be able to make enough more to save more, even considering higher rent. And, if they really move out of such an expensive area before retirement, they might be better off for it.
I guess it just shows that no one number easily can explain our sitch, whether it's our "debt," our spending, our income, our net worth, etc.