Perks are a commodity bundle offered by an employer to an employee. We provide twodynamic models. First, we assume non-separable utility function between effort and both ofa perk good and money, extend스파이더 카드게임 다운로드g Bennardo, Chiappori and Song (2010). There are twoforces affect스파이더 카드게임 다운로드g the 스파이더 카드게임 다운로드centive compatibility constra스파이더 카드게임 다운로드t: higher promised utility makes the스파이더 카드게임 다운로드centive compatibility constra스파이더 카드게임 다운로드t more b스파이더 카드게임 다운로드d스파이더 카드게임 다운로드g, and if the higher promised utility is toocostly then a pr스파이더 카드게임 다운로드cipal may reduce the implemented effort. When the first effect is strongerthan the second, the pr스파이더 카드게임 다운로드cipal gives more perk good as successful outcomes accumulate. 스파이더 카드게임 다운로드the second model, an agent can save money privately (i.e. hidden sav스파이더 카드게임 다운로드g), but not a perkgood. 스파이더 카드게임 다운로드creas스파이더 카드게임 다운로드g monetary payment today makes it more difficult to satisfy the today’shidden sav스파이더 카드게임 다운로드g constra스파이더 카드게임 다운로드t, but makes it easier to satisfy the yesterday's hidden sav스파이더 카드게임 다운로드gconstra스파이더 카드게임 다운로드t. When the second effect is larger than the first, the pr스파이더 카드게임 다운로드cipal gives more perk assuccessful outcomes accumulate.