Compare the operating models
A fictional supplier stocks screws, paint and repairable projectors. Screws are interchangeable, paint complaints refer to the supplier batch, and projector repairs must identify the exact returned machine. Tracking every screw individually would add work without answering a useful question.
| Business requirement | Quantity or lot | Individual serial |
|---|---|---|
| Loose screws | SKU and quantity suffice | Large capture burden |
| Paint from batch P6 | SKU, batch and quantity | Unit detail adds no supplied need |
| Projector PR17 | Cannot identify the repaired unit | Model plus serial and service history |
Work through the chosen model
Keep product identity in all three models. Add a lot entity when shared origin or date matters; add a unit entity when condition, warranty service or rental history follows one physical unit. Receive five projectors as five unit records, not one serial on a five-unit line.
- Ask what must be found after sale
- Capture quantity, lot or unit at receipt
- Carry that identity through dispatch and return
More detail increases receipt, picking and return capture work. Start with the question the business must answer; do not choose serial tracking merely because the software offers it.
Choose quantity-only screws, lot P6 for paint and unit PR17 for the projector. A returned PR17 reopens that unit’s history; another projector of the same model cannot replace its identity.
When the other model fits
A paint supplier now needs each container’s refill history. Is lot-only tracking enough?
Show the worked answer
No. Add individual container identity while retaining the shared batch link where needed.