Depends on what comes through the door.  I have a handful of clients that are easy returns that never change jobs or banks so that I am confident I have all of there information when they bring it in.  If they are in the last week of January I will prepare their returns, otherwise the first week of February is the official start.  I don't play the game of "I have to hurry up and file to beat my ex".  Those folks can gladly go elsewhere, I'm not interested in playing those games.

And I also am not sitting on the edge of my seat asking, "what is the exact time that I can officially start transmitting returns?"  I will wait a day or two for the smoke to clear after the opening of e-filing.  Life is too short to trust Intuit not to screw things up when the avalanche hits.