If you need an item by a certain deadline I would mention this to the seller when bidding.  I recently bid on an item I intended to use as a Valentine's Day gift.  The item was paid for on the 31st of Jan.  I thought two weeks was plenty of time to receive the gift.  I paid for 2-3 day shipping of the item.  Little did I know it meant 2-3 days of the seller's choice.  Needless to say I did  not receive the item until 25 days later.