Trouble with bidding is that you can get drawn into paying more that you want. The whole point to entering an auction is to decide before you start bidding, what the object is worth and how much you are prepared to pay for it.
Therefore, on that basis it's best to get your bid in early to your limit and all those trying to pick up a bargain will get put off by keep missing out when they try and top your bid.
Hopefully the bidding will never reach your top figure and you'll pick up a bargain! 
(doesn't always work though!
)