Prioritising by urgency is far more common, and many people, consciously or unconsciously, prioritise by urgency on a more or less continuous basis.
Unfortunately, the effect of using urgency as our criterion for what to do first is very detrimental. The tendency is to wait to do something until it becomes urgent. The result is that life is lived in a constant rush of impending deadlines. This is very stressful, the quality of work is lowered and reliability is lessened. The benefits of working ‘little and often’ on a project are seldom realised. Finally, one is never able to take full advantage of the amount of time that one has been allocated to complete a project