Derek Thompson: The savings advice that most of these authors give which is really at variance with what economic theory would tell you to do. He says instead of scrimping and scrounging and struggling one year and then kind of overindulging the next, maybe life would be more pleasant on average if you consumed a similar moderate amount in both periods. "I think this is 40 widespread common wisdom that you should be saving 10 to 15% of your income," he said.