Silent Strategy

Went to a silent auction after work today and had to submit one bid for all 3 units, winner take all. Two of the three had nothing but broken furniture, third all boxes with little showing. I didn't really want it, but threw in a low bid anyway and didn't win. Any different strategy at these types of auctions?

Only way I do it, is try to size up both the unit and the competition. Try to figure out what the highest bid could be, and add 5 - 10% to that, if the unit is worth that.