Because folks tend to wait to the last minute and bid reserve plus a dollar (or like amount). As a seller this is disappointing; you'd rather get several folks excited and bid it waaay up
Seriously, as a seller, it can be frustrating to have your item sell for only your reserve; as there are 2 ways to look at a reserve;
1. The minimum amount you hope to get
2. A lower amount, but hopefully so no matter what the item sells...
There is a difference in the two.
I wish many "buyers" would try selling 5-10 items themselves and see the advantages and disadvantages in selling; i.e. lower amounts than hoped, items not selling or not getting bids, if on ebay, you still get whacked with a fee, whether the item sells or not; on gunbroker, any "extras', such as counter, bold, etc still cost you each time it lists; then paypal fees, it all amounts up to a lot of irritation and cost to the seller; which the buyer never sees
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