Time is an abstract concept, and while days and years have some relevance to the world as it exists, all our other units -- minutes and hours, weeks and months -- are completely arbitrary divisions of time into units we can deal with.

My employer seems to have a Zen-like understanding of the irrelevance of arbitrary units of time as they relate to when I get my paycheck. Sadly, my landlord is not so enlightened on the question of when he gets my rent.