But for most of us,future incomes are uncertain.Our earnings can go up or down;we can be promoted or demoted,or even lose our jobs.And if we delay buying a house or investing in a college education,we risk price rise increases that could make such purchases less affordable(担负得起的). How should we take these uncertainties into account when making major consumption or investment decisions? But for most of us, future incomes are uncertain. Our earnings can go up or down; we can be promoted or demoted, or even lose our jobs. And if we delay buying a house or investing in a college education, we risk price rise increases that could make such purchases less affordable(担负得起的). How should we take these uncertainties into account when making major consumption or investment decisions?