What is the origin of the idiom "err on the side of something" and when to use it?

The idiom "err on the side of something" suggests a cautious or conservative approach when making a decision or taking action. It originated from the idea of avoiding mistakes or errors by leaning toward the safer, more careful side of a choice. This expression is used to encourage individuals to choose the less risky option or make a decision that prioritizes safety, prudence, or moderation.