Good luck! We did that with envelopes rather than jars back when we were starving students. My middle child has since independently discovered the same idea :) We don't do it anymore as the way we work with finances makes it slightly illogical, the closest I come is drawing X amount of money out every fortnight and making that last til next pay (and if it doesn't well too bad, it's just "extras" money and basically whether we eat out or go on an excursion to some place that costs a bomb to get into or not XD)