What is the origin of the idiom "fall through the cracks" and when to use it?

The idiom "fall through the cracks" is a metaphorical expression that originated from the idea of something slipping or dropping through the gaps or openings in a structure, much like an object falling through the gaps between floorboards or the cracks in a pavement. In a figurative sense, it came to be used to describe situations where individuals or things are overlooked or neglected within a system, process, or set of rules. The phrase is used to convey the idea that despite efforts to create a comprehensive or foolproof system, there are inherent flaws or oversights that allow some elements to escape notice or attention.