I agree with powderpuff on this. I am a confirmed sniper. I usually don't bid at all until the last seconds of an auction. If I do put in a bid, it's for one of two reasons: to let friends know I am interested, or to discourage the seller from accepting a BIN offer from someone else.
For example, I collect ladies Art Deco wristwatches and there is another EBayer who collects the same type. We have a general agreement that if one of us has bid, the other won't drive the price up by competing.