What MMM does not really address (nor any Mustachians, that I can find), is how a double income family can save so much with child care being so expensive. MMM had the foresight to not have children until he was FI, but most people have kids already, and that means daycare. Currently, my wife and I spend $1650 a month for 2 kids childcare expenses. This price is actually lower than last year because my oldest just started half day kindergarten. Last year we were paying close to $2000 per month. We don't live near family, and we cannot imagine putting our kids into some crappy childcare facility (you know the one, called Nana Banana's fun fun childcare or some garbage for $450 a month). What do other people do?
I liked the response you got with the itemized list. To add to that...
Have you considered one of you getting a 2nd job or developing another stream of income from consulting? It is obvious to say, but to put money away, you either have to spend less or earn more.
The care for our child was done by a local woman who was highly recommended by our neighbor. It was around 700/mo. When the kid was old enough for preschool, we paid about the same for that. Once he got into public kindergarten at a local magnet school, it was nice not having the payments. Now we just have the $1K summer playground cost.
Initially, the Mrs and I were splitting the cost of the daycare and having pretax money put aside for that. When she went from working 5 days to 4, at which time I had a salary increase, I paid for it all.
Also, recently, after 20+ years doing Information Technology work, I am finally getting overtime, plus I can work at home. This is something that kept me from having to get a 2nd job to pay down the house faster. My gross pay last year was 25% higher than my base salary.
Our mortgage payment of $2,100 (1/2 principal) is now getting an extra $1,300 per month. If our jobs hold out, we'll have the house paid off in 4 years instead of 8. (I'm 54 now.) I live in the Balto. suburbs where $250K gets you a small house.
I sold my new Mustang and am now driving an old Corolla that used to be my Mom's. She stopped driving at 87.
YMMV