It simply doesn't add up. Our income is the same every month, but our expenses seem to change every week. The kids need new books for school. The car needs a repair. A cold snap hits but we can't afford to turn up the heat, so the baby gets sick. Anyway, how can we even know if our 'budget' is working? This month's gas bill won't arrive until the middle of next month. Who knows what expenses we'll have between now and then?