Well, I don't buy very high-end stuff on ebay. In fact, most things I have purchased there are common enough that the same item shows up time and again. For example, I wanted to get some triple-beam balances for a program I help administrate. I did a little research to see what they were going for in recently completed auctions and used that to choose a price on the low end of the range that I was willing to pay. After about 20 tries spanning a couple of months, I had finally won the two balances that I needed for the following summer.

When you are talking about rare items, you have a different set of parameters with which you must deal. So perhaps because I just don't have the snipers mentality, I'm not going to get caught up in the psychology of sniping. others mileage may vary, of course.