About one-third of American households live "hand-to-mouth," meaning that they spend all their paychecks. But what surprised the study authors is that 66% of these families are middle class, with a median income of $41,000. While they don't have liquid assets, such as savings accounts or mutual fund holdings, they do have homes and retirement accounts, with a median net worth of $41,000. ... Poor hand-to-mouth households, by contrast, typically have incomes of $21,000 and no assets. Families that don't live paycheck to paycheck have incomes of $51,000 and assets of $116,000. Those living paycheck to paycheck have a tougher...