step 1, analyze all your receipts, bank statements, and credit card bills from a month period 2 – determine what expenses are necessary (rent, utilities, car payments, groceries) 3 – subtract what you need to pay for from your expected after-tax income 4— the rest is discretionary – if you like to shoe shop, set asside how ever much of your discretionary income you want to spend on shoes, and use no more than a quarter of that every week on shoes