One can generally convert all things to dollars. There's generally a price you can offer to convince someone to do most things, such as your example of spending

One can generally convert all things to dollars. There's generally a price you can offer to convince someone to do most things, such as your example of spending time away from family. Sure, money can't buy happiness, humans are weird about non-transitive preferences (if a is preferred to b and b is preferred to c, it turns out that sometimes c is preferred to a), and some things like ethics end up at infinite dollar value... but whatever, this is just a model. You can make it as complex/realistic as you think is necessary.