Keeping receipts is all great but the reason you need an "expenditure diary" is because there are things you'll spend your money on but won't get a receipt. When you record all your expenses it will not only make budgeting easier but at the end of the year you'll actually know how much money you spent on non-essential items. Buying snacks worth $2 every day for example will see you spend well over $600 a year. It's when you look at the figure at the end of the year that you'll notice how much money you'd have saved. Do you do this?