Step Two: Limit Your Needs to 50 Percent of Your After_Tax Income. Now go back to your budget. How much do you spend on "needs" each month, things like groceries, housing, utilities, health insurance, car payment, and car insurance? According to Warren and Tyagi and their 50ቺተ rule, the amount that you spend on these things should total no more than 50 percent of your after_tax pay.
By listing all of your sources of income against all of your monthly expenditures (from required expenses like mortgage or rent payments to discretionary spending like eating out or going to the movies), you get a true picture of your personal cash flow, which will allow you to make better and more informed financial decisions. An accurate budget will also help you to answer that ever elusive question, "Can I afford it?"