What is the origin of the idiom "half the battle" and when to use it?

The origin of this idiom is believed to have originated in a military context. During wartime, soldiers often faced numerous challenges and obstacles before achieving victory. Overcoming the most difficult obstacle was seen as a significant accomplishment, putting them halfway towards their ultimate goal of winning the battle. Over time, the phrase began to be used more broadly to describe situations where overcoming a significant obstacle or challenge was seen as a key part of achieving success.