Parkinson's law
expressionops culture
'Work expands so as to fill the time available for its completion.'
Cyril Northcote Parkinson opened his 1955 Economist essay with the line, drawn from watching bureaucracies grow regardless of workload. Engineers meet it in every padded estimate and every sprint that fills exactly to its deadline. His same book gave the field the law of triviality, better known here as bikeshedding.
Work expands to fill the time available for its completion. Parkinson published it in 1955 as satire about the British civil service, and it has survived because it describes something real about how estimates and effort interact.
The mechanism is not laziness. Given more time, people add polish, explore alternatives, hold more meetings about the approach, and raise the standard of what counts as finished. Each of those is defensible individually, and the aggregate is a task that consumed its budget regardless of what the budget was. This is the same author who gave us the law of triviality, which is where bikeshedding comes from, and the two are related observations about how organizations spend attention.
The practical use is deadline design rather than deadline pressure. Shorter timeboxes genuinely produce faster completion for well-understood work, which is the honest core of the law. It is a bad principle to apply universally, though: for work whose scope is genuinely unknown, a tight deadline does not compress the work, it compresses the quality, and the difference between those two outcomes is invisible until much later.