This was my belief for many years, but then I tried sniping (with the same prices I was putting as my maximum bid before!) and my success rate skyrocketed and the prices I was paying dropped.

It seems that despite repeated reminders and explanations, there are three groups of people using eBay "incorrectly" that make the sniping strategy viable: 1) People who do not understand proxy bidding and think that they "need" to repeatedly bid in increments. 2) People who are irrational about their price ceiling and are willing to bid above their price ceiling because they want to "win". 3) People who want to drive up the price either to deprive others of a good deal, or to drive up the price on behalf of the seller by starting a bidding war with the two above groups.

From a sellers perspective it is common to deal with buyers who won't pay because they paid "more than they wanted", although this is against the eBay ToS and a bid is a contract to purchase the item, because there are few consequences for not doing so.

For some reason, auctions with more bidders seem to attract more bidders, whereas auctions with zero bids seem to go unnoticed. I wonder if this has to do with eBay's search ranking algorithm or some other irrational behavior that I don't understand. At any rate, bidding with 5 or less seconds left to go seems to defeat the above behaviors. I find it distasteful and irrational but it works so I put up with it.

eBay's reputation and trust network is really what makes it a viable product at this point. Given how unreliable Facebook Marketplace buyers are and how many scams are present, I would hesitate to conduct any major transactions beyond a local area.

Snipers essentially convert the ascending-bid proxy auction used in eBay into a Vickrey second-price sealed bid auction, allowing a buyer to not reveal their preferences to other participants. In theory, with rational participants, this shouldn't have any effect on revenue. In practice, buyers do not always understand auction mechanics and delay setting the highest price they're willing to pay until they are outbid. If they're outbid 3 seconds before the deadline, they lost.

Establishing the price ceiling is difficult, though. You might arbitrarily set it as $23, but be sniped at $23.30. The sniper bot only needs to bid that small increment over your arbitrary ceiling.

Can you really say that $23 was your hard limit, or would you have paid $23.40? Unless you're buying something also available at retail, nobody can be that accurate in foresight.

Sniping removes the 'contemplation window' to reconsider your bid.

The act of bidding itself shows interest and raises the price.

From what I understand, the reasoning behind the snipe method of bidding is to avoid showing to other bidders that there is interest, leading to the, supposed, outcome of more likely being the only bidder and thereby receiving the item at the sellers starting bid price (or slightly above) rather than at the "max one was willing to pay" price.

Sniping is the only way to bid for two reasons:

- bidding more than once and allowing time for others to counter bid drives up the price through competition for the item. Sniping also removes the temptation to counter bid, rather than to stick to your maximum bid.

- not sniping allows the seller to do ghost bidding, letting them discover your maximum price (including counter bidding). Here someone always out bid you (the ghost bidder) but the seller says the winner didn't complete the sale so offers it to you at your highest bid.

I have lost most of my bids to bots. Bots will literally bit at hh:59:59. The ceiling value doesn't work unless you bid way above the asking price.

Auto bid isn't the same as sniping. Sniping hides information about demand. Auto bid can't hide information as soon as there is another bidder.