Fungibility refers to the quality that makes something easily exchangeable or replaceable with another item of the same kind because they are identical in value and function. For example, cash is fungible since any bill of the same currency and value is just as good as another. When we prioritize what we must do over what we want to do, we treat the time of our life as if it were fungible, but it isn't. Each point in time is unique because we are constantly changing, our environment evolves, and the people around us are never quite the same. As such, each moment holds different experiences, emotions, and opportunities that may never be replicated. In short, some experiences can be enjoyed only at certain times. People often tell new parents to savor every moment because it’s fleeting. This wisdom applies to all of life and is just as often ignored.