While there is no perfect number, I've seldom seen a live auction that benefited from having more than 20 items in it.  

Keep in mind, most of you are also presenting a great silent auction.  Don't be afraid to put some of those great items on a silent table or two.  

It's a common misconception that silent auctions are not effective for raising the big dollars. Don't get me wrong, I understand there's an earned reputation of under performing silent auctions.  Frequented by "deal seekers".  But that's only part of the equation.

Trust me, put a few "almost live" items in your silent and watch your guests fight over, and run the price up, right up to the closing.