Compare suppliers by how quickly stock sells, average profit, defects and time-to-sale rather than just cost per item. A source is only good when its stock sells. Track what each buying route produces instead of judging it by how cheap the haul looked.
What matters most
The easiest way to think about how to track supplier performance is to keep it simple. Use the facts you know, keep the important details together and learn from what actually sells.
- Tag stock by supplier
- Track damaged or unsellable rate
- Compare average days to sell
- Reorder from evidence, not promises
A practical workflow
- Start with the item or decision. Record the facts you know before changing price, listing details or stock status.
- Check the money. Use purchase cost, expected or actual sale price, fees, postage and packaging so the outcome is based on profit after costs.
- Make one clear change. Change the factor most likely to matter instead of editing everything at once.
- Track the result. Save what happened so future sourcing, pricing and listing choices get better.
- Review in batches. Weekly or monthly reviews are more useful than reacting emotionally to one item.
Numbers worth tracking
You do not need a giant spreadsheet. These few numbers are usually enough to tell whether things are working:
Common mistakes
- Buying because something is cheap
- Using seller-provided retail values
- Ignoring defect and unsellable rates
- Scaling a supplier before testing the stock
What to do next
Try this on a small group of real items first. If it helps, make it part of your normal routine. There is no need to change everything at once.
Related guides
Car Boot Sourcing Guide for Resellers
Car boots reward speed and product knowledge, but a cheap item is still bad stock if demand is weak.
Charity Shop Sourcing Guide
Charity shop sourcing works best with a focused hit list and knowledge of categories your local shops underprice.
Rag House Sourcing Guide
Rag houses can produce strong profit left after costss but require fast grading and a clear idea of what you can actually sell.
Quick questions
Do I need special software for this?
No. You can start with a clean spreadsheet or notes. Software becomes useful when you have enough stock that manual updates are slowing you down or causing mistakes.
How often should I review it?
For active sellers, a quick weekly check plus a fuller monthly review is usually enough to spot problems before they become expensive.
Should I optimise for the highest possible sale price?
Not always. Money coming in and going out, days-to-sell, risk and the amount of work involved can make a slightly lower but faster, cleaner sale more profitable overall.