Opportunity Cost

Never think of money in terms of numbers. Only think of money in terms of other things.

For example, two weeks of "banking" or "architecture" (or whatever job you do) equals a First class ticket to Zurich. If you think of money simply as numbers then you're doomed.

This refers to the "opportunity cost" of money and purchases. When not spending money on a particular item that you want, you are sacrificing the utility of it for: more interest the next time interest is credited, a better credit rating, peace of mind and the ability to buy something else.

You could buy a Bentley, but you could also buy a lot more than one car (all different) for the same amount. -- from JacksonFront

This applies to more than money. It's one of the justifications of YouArentGonnaNeedIt -- think what else you could do in the time you spend on something you won't be using.

It's a key concept in all planning, I think. Whenever planning to do something, what are the consequences in terms of things you now cannot do?

(...unless you work for the government or a large corporation: Then, any money you fail to spend will be taken away from you -- and you'll get less money next year. ;-)

Instead of thinking of money in terms of other things, try thinking of money in terms of time. TimeIsMoney.