Why people run out of money

I’m writing an article for “U.S. News & World Report” about why people often find themselves lurching to paycheck. Obviously, some professions don’t pay enough money to live on, but the rest of us presumably aren’t saving money, aren’t budgeting, are doing too much impulse shopping, etc. If you’re a financial expert (i.e., an accountant, financial advisor, college professor who teaches a finance course), and you have suggestions on how people could keep themselves from running out of money, please drop me a line.