Use 'in tatters' to describe something physically ruined or torn apart. The earthquake left the roads in tatters.
Pro Tip 2/3
Metaphorical Use
Use 'in tatters' metaphorically to describe situations beyond repair. The scandal left the company's image in tatters.
Pro Tip 3/3
Abstract Concepts
Applies to intangible things, like plans or relationships, that can't literally be torn. Their plans for vacation were in tatters after the flight cancellations.