My husband and I never used to budget or track our expenses at all - we were both naturally frugal and always had plenty of money saved up at the end of the month.
But after finding MMM and finally getting around to reading Your Money or Your Life last week, I'm inspired to keep better track in hopes of cutting back even more. I'd love it if we could keep track of every dollar; it satisfies my ISTJ detail-oriented enthusiasm for personal finance. This horrifies my INFP husband, who's fine with a general idea of our expenditures, but thinks keeping track of anything under $10 or $20 is not worth our time and mental energy, especially since it's nothing compared to our combined gross incomes >200K. I argue that for me, it's essentially a hobby, that small, frequent purchases certainly add up, and can contribute to a significant percentage of our expenses, which are low.
Our compromise is that I can get as detailed as I want by looking at our credit and debit card statements, I don't force him to keep track of where cash he withdrew from the ATM went (he doesn't use much cash anyway), and he will write down our laundry expenses at the expensive laundromat across the street as a favor to me.
Of course it's a bit unfair posting this on MMM, but I was curious how closely other people tracked. Do you go down to the penny? Do you just look at the total on the credit card bill at the end of the month? Or do you just try not to spend a lot of money in general and think mindfully about each purchase? (our previous approach)