“Work expands to fill the time available for its completion.”
Source: C. Northcote Parkinson
If you allow two weeks for a two-hour task, then the task may expand – in complexity – more than is needed.
If you direct an individual to do a task, on what basis are you calculating the deadline?
Are you giving two weeks, because you think the work volume and complexity will fill that timeframe? Or is your calculation arbitrary? Are you allowing additional time as a buffer for the individual’s competing priorities?
One suggestion is that instead of saying ‘can you do this by next week’ – which an individual may, as is human nature, complicate and expand, to use the full week – to instead say, ‘can you spend maximum one hour on this task, sometime in the next week’.
This indicates the time that is expected to be spent on the task, while also acknowlegding an individual has competing priorities and tasks to complete.
This way of directing individuals is also consistent with the goal of being ‘sharp and clear with your instructions’.
There are some undeveloped concepts and useful responses here – for further thought.