Cut and dried

Something that is clearly defined, settled, or straightforward with no ambiguity or room for debate. It describes situations or decisions that are obvious and require no further discussion.

This phrase comes from the herb and timber industries of the 17th century. 'Cut and dried' herbs were ready for sale and use, unlike fresh herbs that might spoil. Similarly, cut and dried lumber was processed and ready for construction, representing something finished and ready to use.