It’s human nature to fill the time and space available to us. This phenomenon, known as Parkinson’s Law, states that, “Work expands so as to fill the time available for its completion.”
Other variations of the principle include “The more money you earn the more money you spend,” or “The bigger the available space, the more junk it can hold.”
This principle comes from the opening line of a humorous essay by Professor Cyril Northcote Parkinson published in The Economist in 1955.
The essay explains the results of a study he conducted of the British Civil Service. The British Civil Service grew between 1914-1928, with a noticeable rise in administrative positions and a concurrent decline in ‘fighting’ positions. In 1914 there were 2,000 Admiralty officials with this number growing to 3,569 in 1928, creating “a magnificent Navy on land.” The interesting part of this shift, however, is that this growth was unrelated to any possible increase in their work. The British Navy during that period had diminished by a third in men and two-thirds in ships. From 1922 onwards it was limited by the Washington Naval Agreement, signed among the major nations that had won World War I, which limited naval construction to prevent an arms race. Thus, the number of people employed in the bureaucracy increased even as the British Empire collapsed — an event that decreased the amount of work available.