Let the beer tell you how long to ferment. When the krausen falls and the beer starts to clear you know it's just about finished, so if kegging, give it a couple more days after that and take a gravity reading. If it's at FG, you can keg it. If you are going to transfer to secondary, don't bother waiting the two days, take a gravity reading and if its at or within a couple of points of FG, transfer to secondary. If bottling right from primary, maybe give it another week after it begins to clear, rather than just a couple of days, to make sure that it is really done.