Money, time, and effort previously spent to advance a project are lost in the past. You can’t get them back. They are “sunk.” Logically, when you decide whether to pour more resources into a project, you should consider only whether doing so makes sense now. Sunk costs should not be a factor in your thinking—but they probably will be because most people find it incredibly hard to push them out of their minds. And so people commonly “throw good money after bad,” to use the old phrase.
