Avoid Duplicate Tracking Numbers
Make sure that tracking numbers being used ARE NOT duplicates within the 180 day period required by eBay. If tracking numbers are re-used within this time period (specifically STAMPS.COM /USPS tracking), eBay will reject them and then apply a defect to our account. One too many defects and our rating is lowered and our fees discount is affected. It's not just an inconvenience but a financial cost if this isn't corrected.