Determine how much money you 'll need on a monthly basis for as long as40 years from now, says Sandy Timmermann, director of Mature Market Institute, a research division at MetLife Inc. 大都会保险(MetLifeInc.)的研究机构MatureMarketInstitute的负责人桑迪?蒂默曼(SandyTimmermann)说,判断一下从现在起最长40年,你每个月需要多少钱。