Why grocery is harder than fashion
Perishables, substitutions, and SLAs compound
Time is inventory
A fashion SKU on a shelf is mostly stable. A grocery SKU is a clock. Pick sequence, route design, and stock rotation are fulfilment problems — not merchandising polish.
Substitutions are operational debt
Every substitution is a pick decision, a customer comms decision, and often a margin decision. Fashion can skip the line; grocery cannot.
Track substitution rate and root cause in your WMS — not in a monthly ops review slide.
Build for exceptions first
Dark Store Systems and Bud prioritise exception handling on the floor because grocery shifts are exception-heavy. Perfect happy-path demos miss the point.