In working on a project, one can and will always work at an efficiency level precisely correlated to the amount of time available to complete it.  This is such that the amount of time it takes to complete a project is exactly the amount of time one has to do it, much as the goldfish, given enough food, will grow to fill his bowl. 

Case in point:

"I need you to do X,Y and Z.  How long will that take you?"
"How long do I have?"

Extrapolation:

There is no such thing as finishing early, nor is there necessarily motivation to do so.  The reward for finishing a set task early is usually recieving another task to do.  This is known as the "Efficiency Penalty."