Key Takeaway: None of these mistakes look like a crisis in the moment. Together, they're a steady, quiet drain on margin that's easy to miss without looking for it directly.
What's on This Page
1. Duplicate Orders
When more than one person can place orders without shared visibility, the same SKU gets reordered twice. See Purchase Cost Control.
2. Paying Invoices Without Verification
Skipping the 3-way match between PO, receiving record, and invoice means overbilling and short shipments go unnoticed.
3. Buying on Price Alone
A cheaper unit cost from a slower, less reliable supplier often costs more in stockouts than it saves. See Supplier Selection Guide.
4. No Reorder Point, Just a Feeling
Ordering when a shelf "looks low" leads to both panic rush-orders and missed early-order discounts.
5. Never Reviewing Supplier Price Trends
Small, gradual price increases go unnoticed without comparing pricing across purchase order history over time.
6. Treating Purchasing as Separate From Inventory Planning
Buying decisions made without checking current stock and forecasted demand lead directly to overstock or stockouts.
For further reading, see the Association for Supply Chain Management (ASCM).
Checklist
- Check for a shared, visible record of open purchase orders
- Confirm invoices are matched to POs before payment
- Review whether purchasing decisions consider supplier reliability, not just price
- Verify reorder points exist rather than relying on visual checks
- Check supplier price trends over the last several orders
- Confirm purchasing and inventory planning are connected, not separate
Common Mistakes
FAQ
What's the single most preventable purchasing mistake?
Duplicate orders. A shared, visible record of open purchase orders eliminates most of them immediately.
How much can these mistakes actually cost a small business?
It varies, but duplicate orders, missed discounts, and overbilling combined can represent a meaningful percentage of total purchasing spend over a year.
Is buying on price alone ever the wrong call?
Often, yes, when it comes from a slower or less reliable supplier. The savings can be outweighed by stockout and rush-order costs.
What's the fastest fix among these common mistakes?
Implementing a 3-way match before paying invoices. It's a process change, not a system overhaul, and it catches overbilling immediately.
Calculate This For Your Business
Related Guides in the Purchasing Academy
- Purchase Cost Control. the specific fix for the most common mistake
- Purchase Planning Explained. the process that prevents most of these
- Purchase Orders Explained. another guide in the Purchasing Academy