What is the origin of the idiom "draft mule work" and when to use it?

The idiom "draft mule work" has its origins in agricultural practices. It refers to demanding tasks that were traditionally assigned to mules, which were strong and sturdy animals commonly used for pulling heavy loads, particularly in farming and construction. In this context, "draft" refers to the act of pulling or carrying a heavy load. This idiom is used metaphorically to describe heavy manual labor and tasks that require significant physical effort, often involving repetitive or monotonous actions.