Suppose . Steve Waldman says recent events have shown :
Economists talk about consumption smoothing, how it may be optimal for a consumer whose income is volatile to borrow during periods of low income and repay (or save) during periods of high income in order to maintain a constant standard of living. That’s very well in models where consumers know the true distribution of their future income, where the spread between borrowing and lending interest rates is not very large, and where consumer preferences are time-consistent. In practice, none of these conditions hold even approximately.
He concludes :
consumers ought to borrow only to counter severe downward shocks to income, pay off borrowings quickly, and build buffers of precautionary savings, since the cost of dissaving is much less then the cost of borrowing.