Mind & EverydayMental model
Work expands to fill the time available for its completion.
Cyril Northcote Parkinson wrote the line in 1955 in a satirical Economist essay, after watching the British naval bureaucracy grow while the fleet shrank. As a thinking tool it is serious: a task with no deadline eats the whole day; the same task with a 45-minute deadline gets done in 45 minutes. The deadline is a filter for what matters.
Useful: Give routine tasks a tight, artificial deadline before you start.
Source: en.wikipedia.org