I bid early because then it means I won't be tempted to go over how much I want to pay for the item. It's no different from sniping in that I've put in my maximum amount, and if someone bids over that then it's no problem because it's no longer a bargain, whereas if you snipe and someone has a max bid higher than you or also snipes with a higher bid then there's no time to make another bid.
I also believe that having bids on an item with lots of time left puts other people off bidding on it.
I bid early because then it means I won't be tempted to go over how much I want to pay for the item. It's no different from sniping in that I've put in my maximum amount, and if someone bids over that then it's no problem because it's no longer a bargain, whereas if you snipe and someone has a max bid higher than you or also snipes with a higher bid then there's no time to make another bid.
I also believe that having bids on an item with lots of time left puts other people off bidding on it.