It is hard to convert the psychological cost into actual money. First off compare the vacation with what you would do as an alternative. Then you should compare it with the amount of time and effort you have to put in, with the money you earn for a vacation.
Work Step by Step
1. try to think of how you would value effort in terms of money. 2. compare the alternatives to a vacation. 3. Think about how much work you have to do to earn money, for a vacation