I watch stuff all the time to see what it sells for. I then bid on a similar item and forget about it till the auction is over. I don't get into bidding wars and don't lose sleep over losing something by one dollar. Unless it's something rare like a French-sized seatpost, there will be another one along shortly.

I also watch items that are way overpriced just to see if somebody actually bids on it. Or the really cool stuff.