Why failed short wars can become long wars

Why describe wars in horizons of six hours, days, weeks, months, or years?

It is a rule of thumb: when a war survives one short decision window, mobilization, supply, and political commitment can push it into the next and much longer horizon.

The sequence is a rule of thumb rather than a rigid law. The Second World War's 1939-to-1945 span illustrates the six-year horizon, while the First World War and its aftermath sit near the same pattern. A campaign that fails to decide the issue in its opening hours can give the defender time to organize through days, weeks, months, and eventually years. Very long labels such as the Hundred Years War instead cover repeated campaigns and pauses in which the combatants rearmed. Applied to Ukraine, the failed opening gamble allowed outside support and national mobilization to turn a planned rapid victory into a sustained war of attrition.